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less(1)
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LESS(1) General Commands Manual LESS(1)
NAME
less - display the contents of a file in a terminal
SYNOPSIS
less -?
less --help
less -V
less --version
less [-[+]aABcCdeEfFgGiIJKLmMnNqQrRsSuUVwWX~]
[-b space] [-h lines] [-j line] [-k keyfile]
[-{oO} logfile] [-p pattern] [-P prompt] [-t tag]
[-T tagsfile] [-x tab,...] [-y lines] [-[z] lines]
[-# shift] [+[+]cmd] [--] [filename]...
(See the OPTIONS section for alternate option syntax with long option names.)
DESCRIPTION
Less is a program similar to more(1), but it has many more features. Less does not have
to read the entire input file before starting, so with large input files it starts up
faster than text editors like vi(1). Less uses termcap (or terminfo on some systems), so
it can run on a variety of terminals. There is even limited support for hardcopy termi‐
nals. (On a hardcopy terminal, lines which should be printed at the top of the screen are
prefixed with a caret.)
COMMANDS
Commands are based on both more and vi. Commands may be preceded by a decimal number,
called N in the descriptions below. The number is used by some commands, as indicated.
In the following descriptions, ^X means control-X. ESC stands for the ESCAPE key; for ex‐
ample ESC-v means the two character sequence "ESCAPE", then "v".
h or H Help: display a summary of these commands. If you forget all the other commands,
remember this one.
SPACE or ^V or f or ^F
Scroll forward N lines, default one window (see option -z below). If N is more
than the screen size, only the final screenful is displayed. Warning: some systems
use ^V as a special literalization character.
z Like SPACE, but if N is specified, it becomes the new window size.
ENTER or RETURN or ^N or e or ^E or j or ^J
Scroll forward N lines, default 1. The entire N lines are displayed, even if N is
more than the screen size.
d or ^D
Scroll forward N lines, default one half of the screen size. If N is specified, it
becomes the new default for subsequent d and u commands.
b or ^B or ESC-v
Scroll backward N lines, default one window (see option -z below). If N is more
than the screen size, only the final screenful is displayed.
w Like ESC-v, but if N is specified, it becomes the new window size.
y or ^Y or ^P or k or ^K
Scroll backward N lines, default 1. The entire N lines are displayed, even if N is
more than the screen size. Warning: some systems use ^Y as a special job control
character.
u or ^U
Scroll backward N lines, default one half of the screen size. If N is specified,
it becomes the new default for subsequent d and u commands.
J Like j, but continues to scroll beyond the end of the file.
K or Y Like k, but continues to scroll beyond the beginning of the file.
ESC-SPACE
Like SPACE, but scrolls a full screenful, even if it reaches the end of the file.
ESC-b Like b, but scrolls a full screenful, even if it reaches the beginning of the file.
ESC-j Scroll forward N file lines, default 1. A file line is a complete line in the
file, terminated by a newline.
ESC-k Scroll backwards N file lines, default 1.
ESC-) or RIGHTARROW
Scroll horizontally right N characters, default half the screen width (see the -#
option). If a number N is specified, it becomes the default for future RIGHTARROW
and LEFTARROW commands. While the text is scrolled, it acts as though the -S op‐
tion (chop lines) were in effect.
ESC-( or LEFTARROW
Scroll horizontally left N characters, default half the screen width (see the -#
option). If a number N is specified, it becomes the default for future RIGHTARROW
and LEFTARROW commands.
ESC-} or ^RIGHTARROW
Scroll horizontally right to show the end of the longest displayed line.
ESC-{ or ^LEFTARROW
Scroll horizontally left back to the first column.
r or ^R or ^L
Repaint the screen.
R Repaint the screen, discarding any buffered input. That is, reload the current
file. Useful if the file is changing while it is being viewed.
F Scroll forward, and keep trying to read when the end of file is reached. Normally
this command would be used when already at the end of the file. It is a way to
monitor the tail of a file which is growing while it is being viewed. (The behav‐
ior is similar to the "tail -f" command.) To stop waiting for more data, enter the
interrupt character (usually ^C). On systems which support poll(2) you can also
use ^X or the character specified by the --intr option. If the input is a pipe and
the --exit-follow-on-close option is in effect, less will automatically stop wait‐
ing for data when the input side of the pipe is closed.
ESC-F Like F, but as soon as a line is found which matches the last search pattern, the
terminal bell is rung and forward scrolling stops.
g or < or ESC-<
Go to line N in the file, default 1 (beginning of file). (Warning: this may be
slow if N is large.)
G or > or ESC->
Go to line N in the file, default the end of the file. (Warning: this may be slow
if N is large, or if N is not specified and standard input, rather than a file, is
being read.)
ESC-G Same as G, except if no number N is specified and the input is standard input, goes
to the last line which is currently buffered.
p or % Go to a position N percent into the file. N should be between 0 and 100, and may
contain a decimal point.
P Go to the line containing byte offset N in the file.
{ If a left curly bracket appears in the top line displayed on the screen, the { com‐
mand will go to the matching right curly bracket. The matching right curly bracket
is positioned on the bottom line of the screen. If there is more than one left
curly bracket on the top line, a number N may be used to specify the N-th bracket
on the line.
} If a right curly bracket appears in the bottom line displayed on the screen, the }
command will go to the matching left curly bracket. The matching left curly
bracket is positioned on the top line of the screen. If there is more than one
right curly bracket on the bottom line, a number N may be used to specify the N-th
bracket on the line.
( Like {, but applies to parentheses rather than curly brackets.
) Like }, but applies to parentheses rather than curly brackets.
[ Like {, but applies to square brackets rather than curly brackets.
] Like }, but applies to square brackets rather than curly brackets.
ESC-^F Followed by two characters, acts like {, but uses the two characters as open and
close brackets, respectively. For example, "ESC ^F < >" could be used to go for‐
ward to the > which matches the < in the top displayed line.
ESC-^B Followed by two characters, acts like }, but uses the two characters as open and
close brackets, respectively. For example, "ESC ^B < >" could be used to go back‐
ward to the < which matches the > in the bottom displayed line.
m Followed by any lowercase or uppercase letter, marks the first displayed line with
that letter. If the status column is enabled via the -J option, the status column
shows the marked line.
M Acts like m, except the last displayed line is marked rather than the first dis‐
played line.
' (Single quote.) Followed by any lowercase or uppercase letter, returns to the po‐
sition which was previously marked with that letter. Followed by another single
quote, returns to the position at which the last "large" movement command was exe‐
cuted. Followed by a ^ or $, jumps to the beginning or end of the file respec‐
tively. Marks are preserved when a new file is examined within a single invocation
of less, so the ' command can be used to switch between input files. The --save-
marks option causes marks to be preserved across different invocations of less.
^X^X Same as single quote.
ESC-m Followed by any lowercase or uppercase letter, clears the mark identified by that
letter.
/pattern
Search forward in the file for the N-th line containing the pattern. N defaults to
1. The pattern is a regular expression, as recognized by the regular expression
library supplied by your system. By default, searching is case-sensitive (upper‐
case and lowercase are considered different); the -i option can be used to change
this. The search starts at the first line displayed (but see the -a and -j op‐
tions, which change this).
Certain characters are special if entered at the beginning of the pattern; they
modify the type of search rather than become part of the pattern:
^N or !
Search for lines which do NOT match the pattern.
^E or *
Search multiple files. That is, if the search reaches the END of the cur‐
rent file without finding a match, the search continues in the next file in
the command line list.
^F or @
Begin the search at the first line of the FIRST file in the command line
list, regardless of what is currently displayed on the screen or the set‐
tings of the -a or -j options.
^K Highlight any text which matches the pattern on the current screen, but
don't move to the first match (KEEP current position).
^R Don't interpret regular expression metacharacters; that is, do a simple tex‐
tual comparison.
^S Followed by a digit N between 1 and 5. Only text which has a non-empty
match for the N-th parenthesized SUB-PATTERN will be considered to match the
pattern. For example, searching for "(abc)|(def)" modified with ^S1 would
search for instances of "abc", but would highlight instances of both "abc"
and "def". (Supported only if less is built with one of the regular expres‐
sion libraries posix, pcre, or pcre2.) Multiple ^S modifiers can be speci‐
fied, to match more than one sub-pattern.
^W WRAP around the current file. That is, if the search reaches the end of the
current file without finding a match, the search continues from the first
line of the current file up to the line where it started. If the ^W modi‐
fier is set, the ^E modifier is ignored.
^L The next character is taken literally; that is, it becomes part of the pat‐
tern even if it is one of the above search modifier characters.
?pattern
Search backward in the file for the N-th line containing the pattern. The search
starts at the last line displayed (but see the -a and -j options, which change
this).
Certain characters are special as in the / command:
^N or !
Search for lines which do NOT match the pattern.
^E or *
Search multiple files. That is, if the search reaches the beginning of the
current file without finding a match, the search continues in the previous
file in the command line list.
^F or @
Begin the search at the last line of the last file in the command line list,
regardless of what is currently displayed on the screen or the settings of
the -a or -j options.
^K As in forward searches.
^R As in forward searches.
^S As in forward searches.
^W WRAP around the current file. That is, if the search reaches the beginning
of the current file without finding a match, the search continues from the
last line of the current file up to the line where it started.
^L As in forward searches.
ESC-/pattern
Same as "/*".
ESC-?pattern
Same as "?*".
n Repeat previous search, for N-th line containing the last pattern. If the previous
search was modified by ^N, the search is made for the N-th line NOT containing the
pattern. If the previous search was modified by ^E, the search continues in the
next (or previous) file if not satisfied in the current file. If the previous
search was modified by ^R, the search is done without using regular expressions.
If the previous search was modified by ^W, the search wraps at the end (or begin‐
ning) of the file. There is no effect if the previous search was modified by ^F or
^K.
N Repeat previous search, but in the reverse direction.
ESC-n Repeat previous search, but crossing file boundaries. The effect is as if the pre‐
vious search were modified by *.
ESC-N Repeat previous search, but in the reverse direction and crossing file boundaries.
ESC-u Undo search highlighting. Turn off highlighting of strings matching the current
search pattern. If highlighting is already off because of a previous ESC-u com‐
mand, turn highlighting back on. Any search command will also turn highlighting
back on. (Highlighting can also be disabled by toggling the -G option; in that
case search commands do not turn highlighting back on.)
ESC-U Like ESC-u but also clears the saved search pattern. If the status column is en‐
abled via the -J option, this clears all search matches marked in the status col‐
umn.
&pattern
Display only lines which match the pattern; lines which do not match the pattern
are not displayed. If pattern is empty (if you type & immediately followed by EN‐
TER), any filtering is turned off, and all lines are displayed. While filtering is
in effect, an ampersand is displayed at the beginning of the prompt, as a reminder
that some lines in the file may be hidden. Multiple & commands may be entered, in
which case only lines which match all of the patterns will be displayed.
Certain characters are special as in the / command:
^N or !
Display only lines which do NOT match the pattern.
^R Don't interpret regular expression metacharacters; that is, do a simple tex‐
tual comparison.
:e [filename]
Examine a new file. If the filename is missing, the "current" file (see the :n and
:p commands below) from the list of files in the command line is re-examined. A
percent sign (%) in the filename is replaced by the name of the current file. A
pound sign (#) is replaced by the name of the previously examined file. However,
two consecutive percent signs are simply replaced with a single percent sign. This
allows you to enter a filename that contains a percent sign in the name. Simi‐
larly, two consecutive pound signs are replaced with a single pound sign. The
filename is inserted into the command line list of files so that it can be seen by
subsequent :n and :p commands. If the filename consists of several files, they are
all inserted into the list of files and the first one is examined. If the filename
contains one or more spaces, the entire filename should be enclosed in double
quotes (also see the -" option).
^X^V or E
Same as :e. Warning: some systems use ^V as a special literalization character.
On such systems, you may not be able to use ^V.
:n Examine the next file (from the list of files given in the command line). If a
number N is specified, the N-th next file is examined.
:p Examine the previous file in the command line list. If a number N is specified,
the N-th previous file is examined.
:x Examine the first file in the command line list. If a number N is specified, the
N-th file in the list is examined.
:d Remove the current file from the list of files.
t Go to the next tag, if there were more than one matches for the current tag. See
the -t option for more details about tags.
T Go to the previous tag, if there were more than one matches for the current tag.
^O^N or ^On
Search forward in the file for the N-th next OSC 8 hyperlink.
^O^P or ^Op
Search backward in the file for the N-th previous OSC 8 hyperlink.
^O^L or ^Ol
Jump to the currently selected OSC 8 hyperlink.
= or ^G or :f
Prints some information about the file being viewed, including its name and the
line number and byte offset of the bottom line being displayed. If possible, it
also prints the length of the file, the number of lines in the file and the percent
of the file above the last displayed line.
- Followed by one of the command line option letters (see OPTIONS below), this will
change the setting of that option and print a message describing the new setting.
If a ^P (CONTROL-P) is entered immediately after the dash, the setting of the op‐
tion is changed but no message is printed. If the option letter has a numeric
value (such as -b or -h), or a string value (such as -P or -t), a new value may be
entered after the option letter. If no new value is entered, a message describing
the current setting is printed and nothing is changed.
-- Like the - command, but takes a long option name (see OPTIONS below) rather than a
single option letter. Press ENTER or RETURN after typing the option name to change
it. You can enter just the beginning of an option name, then press TAB to find all
option names which begin with that string. A ^P immediately after the second dash
suppresses printing of a message describing the new setting, as in the - command.
-+ Followed by one of the command line option letters this will reset the option to
its default setting and print a message describing the new setting. (The "-+X"
command does the same thing as "-+X" on the command line.) This does not work for
string-valued options.
--+ Like the -+ command, but takes a long option name rather than a single option let‐
ter.
-! Followed by one of the command line option letters, this will reset the option to
the "opposite" of its default setting and print a message describing the new set‐
ting. This does not work for numeric or string-valued options.
--! Like the -! command, but takes a long option name rather than a single option let‐
ter.
_ (Underscore.) Followed by one of the command line option letters, this will print
a message describing the current setting of that option. The setting of the option
is not changed.
__ (Double underscore.) Like the _ (underscore) command, but takes a long option name
rather than a single option letter. You must press ENTER or RETURN after typing
the option name.
+cmd Causes the specified cmd to be executed each time a new file is examined. For ex‐
ample, +G causes less to initially display each file starting at the end rather
than the beginning.
V Prints the version number of less being run.
q or Q or :q or :Q or ZZ
Exits less.
The following seven commands may or may not be valid, depending on your particular instal‐
lation.
v Invokes an editor to edit the current file being viewed. The editor is taken from
the environment variable VISUAL if defined, or EDITOR if VISUAL is not defined, or
defaults to "vi" if neither VISUAL nor EDITOR is defined. See also the discussion
of LESSEDIT under the section on PROMPTS below.
! shell-command
Invokes a shell to run the shell-command given. A percent sign (%) in the command
is replaced by the name of the current file. A pound sign (#) is replaced by the
name of the previously examined file. "!!" repeats the last shell command. "!"
with no shell command invokes an interactive shell. If a ^P (CONTROL-P) is entered
immediately after the !, no "done" message is printed after the shell command is
executed. On Unix systems, the shell is taken from the environment variable SHELL,
or defaults to "sh". On MS-DOS, Windows, and OS/2 systems, the shell is the normal
command processor.
# shell-command
Similar to the "!" command, except that the command is expanded in the same way as
prompt strings. For example, the name of the current file would be given as "%f".
| <m> shell-command
<m> represents any mark letter. Pipes a section of the input file to the given
shell command. The section of the file to be piped is between the position marked
by the letter and the current screen. The entire current screen is included, re‐
gardless of whether the marked position is before or after the current screen. <m>
may also be ^ or $ to indicate beginning or end of file respectively. If <m> is .
or newline, the current screen is piped. If a ^P (CONTROL-P) is entered immedi‐
ately after the mark letter, no "done" message is printed after the shell command
is executed.
s filename
Save the input to a file. This works only if the input is a pipe, not an ordinary
file.
^O^O
Run a shell command to open the URI in the current OSC 8 hyperlink, selected by a
previous ^O^N or ^O^P command. To find the shell command, the environment variable
named "LESS_OSC8_xxx" is read, where "xxx" is the scheme from the URI (the part be‐
fore the first colon), or is empty if there is no colon in the URI. The value of
the environment variable is then expanded in the same way as prompt strings (in
particular, any instance of "%o" is replaced with the URI) to produce an OSC 8
"handler" shell command. The standard output from the handler is an "opener" shell
command which is then executed to open the URI.
There are two special cases:
1. If the URI begins with "#", the remainder of the URI is taken to be
the value of the id parameter in another OSC 8 link in the same file,
and ^O^O will simply jump to that link.
2. If the opener begins with the characters ":e" followed by whitespace
and a filename, then instead of running the opener as a shell com‐
mand, the specified filename is opened in the current instance of
less.
In a simple case where the opener accepts the complete URI as a command line para‐
meter, the handler may be as simple as
echo mybrowser '%o'
In other cases, the URI may need to be modified, so the handler may have to do some
manipulation of the %o value.
If the LESS_OSC8_xxx variable is not set, the variable LESS_OSC8_ANY is tried. If
neither LESS_OSC8_xxx nor LESS_OSC8_ANY is set, links using the "xxx" scheme cannot
be opened. However, there are default handlers for the schemes "man" (used when
LESS_OSC8_man is not set) and "file" (used when LESS_OSC8_file is not set), which
should work on systems which provide the sed(1) command and a shell with syntax
compatible with the Bourne shell sh(1). If you use LESS_OSC8_ANY to override
LESS_OSC8_file, you must set LESS_OSC8_file to "-" to indicate that the default
value should not be used, and likewise for LESS_OSC8_man.
The URI passed to an OSC8 handler via %o is guaranteed not to contain any single
quote or double quote characters, but it may contain any other shell metacharacters
such as semicolons, dollar signs, ampersands, etc. The handler should take care to
appropriately quote parameters in the opener command, to prevent execution of unin‐
tended shell commands in the case of opening a URI which contains shell metacharac‐
ters. Also, since the handler command is expanded like a command prompt, any
metacharacters interpreted by prompt expansion (such as percent, dot, colon, back‐
slash, etc.) must be escaped with a backslash (see the PROMPTS section for de‐
tails).
^X When the "Waiting for data" message is displayed, such as while in the F command,
pressing ^X will stop less from waiting and return to a prompt. This may cause
less to think that the file ends at the current position, so it may be necessary to
use the R or F command to see more data. The --intr option can be used to specify
a different character to use instead of ^X. This command works only on systems
that support the poll(2) function. On systems without poll(2), the interrupt char‐
acter (usually ^C) can be used instead.
OPTIONS
Command line options are described below. Most options may be changed while less is run‐
ning, via the "-" command.
Some options may be given in one of two forms: either a dash followed by a single letter,
or two dashes followed by a long option name. A long option name may be abbreviated as
long as the abbreviation is unambiguous. For example, --mouse may be abbreviated --mou,
but not --mo, since both --mouse and --modelines begin with --mo. Some long option names
are in uppercase, such as --QUIT-AT-EOF, as distinct from --quit-at-eof. Such option
names need only have their first letter capitalized; the remainder of the name may be in
either case. For example, --Quit-at-eof is equivalent to --QUIT-AT-EOF.
Options are also taken from the environment variable "LESS". For example, to avoid typing
"less -options ..." each time less is invoked, you might tell csh:
setenv LESS "-options"
or if you use sh:
LESS="-options"; export LESS
On MS-DOS and Windows, you don't need the quotes, but you should be careful that any per‐
cent signs in the options string are not interpreted as an environment variable expansion.
The environment variable is parsed before the command line, so command line options over‐
ride the LESS environment variable. If an option appears in the LESS variable, it can be
reset to its default value on the command line by beginning the command line option with
"-+".
Some options like -k or -D require a string to follow the option letter. The string for
that option is considered to end when a dollar sign ($) is found. For example, you can
set two -D options like this:
LESS="Dnwb$Dsbw"
If the --use-backslash option appears earlier in the options, then a dollar sign or back‐
slash may be included literally in an option string by preceding it with a backslash. If
the --use-backslash option is not in effect, then backslashes are not treated specially,
and there is no way to include a dollar sign in the option string.
-? or --help
This option displays a summary of the commands accepted by less (the same as the h
command). (Depending on how your shell interprets the question mark, it may be
necessary to quote the question mark, thus: "-\?".)
-a or --search-skip-screen
By default, forward searches start at the top of the displayed screen and backwards
searches start at the bottom of the displayed screen (except for repeated searches
invoked by the n or N commands, which start after or before the "target" line re‐
spectively; see the -j option for more about the target line). The -a option
causes forward searches to instead start at the bottom of the screen and backward
searches to start at the top of the screen, thus skipping all lines displayed on
the screen.
-A or --SEARCH-SKIP-SCREEN
Causes all forward searches (not just non-repeated searches) to start just after
the target line, and all backward searches to start just before the target line.
Thus, forward searches will skip part of the displayed screen (from the first line
up to and including the target line). Similarly backwards searches will skip the
displayed screen from the last line up to and including the target line. This was
the default behavior in less versions prior to 441.
-bn or --buffers=n
Specifies the amount of buffer space less will use for each file, in units of kilo‐
bytes (1024 bytes). By default 64 KB of buffer space is used for each file (unless
the file is a pipe; see the -B option). The -b option specifies instead that n
kilobytes of buffer space should be used for each file. If n is -1, buffer space
is unlimited; that is, the entire file can be read into memory.
-B or --auto-buffers
By default, when data is read from a pipe, buffers are allocated automatically as
needed. If a large amount of data is read from the pipe, this can cause a large
amount of memory to be allocated. The -B option disables this automatic allocation
of buffers for pipes, so that only 64 KB (or the amount of space specified by the
-b option) is used for the pipe. Warning: use of -B can result in erroneous dis‐
play, since only the most recently viewed part of the piped data is kept in memory;
any earlier data is lost. Lost characters are displayed as question marks.
-c or --clear-screen
Causes full screen repaints to be painted from the top line down. By default, full
screen repaints are done by scrolling from the bottom of the screen.
-C or --CLEAR-SCREEN
Same as -c, for compatibility with older versions of less.
-d or --dumb
The -d option suppresses the error message normally displayed if the terminal is
dumb; that is, lacks some important capability, such as the ability to clear the
screen or scroll backward. The -d option does not otherwise change the behavior of
less on a dumb terminal.
-Dxcolor or --color=xcolor
Changes the color of different parts of the displayed text. x is a single charac‐
ter which selects the type of text whose color is being set:
B Binary characters.
C Control characters.
E Errors and informational messages.
H Header lines and columns, set via the --header option.
M Mark letters in the status column.
N Line numbers enabled via the -N option.
P Prompts.
R The rscroll character.
S Search results.
W The highlight enabled via the -w option.
1-5 The text in a search result which matches the first through fifth parenthe‐
sized sub-pattern. Sub-pattern coloring works only if less is built with
one of the regular expression libraries posix, pcre, or pcre2.
d Bold text.
k Blinking text.
s Standout text.
u Underlined text.
The uppercase letters and digits can be used only when the --use-color option is
enabled. When text color is specified by both an uppercase letter and a lowercase
letter, the uppercase letter takes precedence. For example, error messages are
normally displayed as standout text. So if both "s" and "E" are given a color, the
"E" color applies to error messages, and the "s" color applies to other standout
text. The lowercase letters refer to bold and underline text formed by overstrik‐
ing with backspaces (see the -U option) and to non-content text (such as line num‐
bers and prompts), but not to text formatted using ANSI escape sequences with the
-R option (but see the note below for different behavior on Windows and MS-DOS).
A lowercase letter may be followed by a + to indicate that the normal format change
and the specified color should both be used. For example, -Dug displays underlined
text as green without underlining; the green color has replaced the usual underline
formatting. But -Du+g displays underlined text as both green and in underlined
format.
color is either a 4-bit color string or an 8-bit color string:
A 4-bit color string is one or two characters, where the first character specifies
the foreground color and the second specifies the background color as follows:
b Blue
c Cyan
g Green
k Black
m Magenta
r Red
w White
y Yellow
The corresponding uppercase letter denotes a brighter shade of the color. For ex‐
ample, -DNGk displays line numbers as bright green text on a black background, and
-DEbR displays error messages as blue text on a bright red background. If either
character is a "-" or is omitted, the corresponding color is set to that of normal
text.
An 8-bit color string is one or two decimal integers separated by a dot, where the
first integer specifies the foreground color and the second specifies the back‐
ground color. Each integer is a value between 0 and 255 inclusive which selects a
"CSI 38;5" color value (see https://en.wikipedia.org/wiki/ANSI_escape_code#SGR).
If either integer is a "-" or is omitted, the corresponding color is set to that of
normal text.
A 4-bit or 8-bit color string may be followed by one or more of the following char‐
acters to set text attributes in addition to the color.
s or ~ Standout (reverse video)
u or _ Underline
d or * Bold
l or & Blinking
On MS-DOS and Windows, the --color option behaves differently from what is de‐
scribed above in these ways:
• The bold (d and *) and blinking (l and &) text attributes at the end of a
color string are not supported.
• Lowercase color selector letters refer to text formatted by ANSI escape se‐
quences with -R, in addition to overstruck and non-content text (but see
-Da).
• For historical reasons, when a lowercase color selector letter is followed
by a numeric color value, the number is not interpreted as an "CSI 38;5"
color value as described above, but instead as a 4-bit CHAR_INFO.Attributes
value, between 0 and 15 inclusive (see https://learn.microsoft.com/en-
us/windows/console/char-info-str).
To avoid confusion, it is recommended that the equivalent letters rather
than numbers be used after a lowercase color selector on MS-DOS/Windows.
• Numeric color values ("CSI 38;5" color) following an uppercase color selec‐
tor letter are not supported on systems earlier than Windows 10.
• Only a limited set of ANSI escape sequences to set color in the content work
correctly. 4-bit color sequences work, but "CSI 38;5" color sequences do
not.
• The -Da option makes the behavior of --color more similar to its behavior on
non-MS-DOS/Windows systems by (1) making lowercase color selector letters
not affect text formatted with ANSI escape sequences, and (2) allowing "CSI
38;5" color sequences in the content work by passing them to the terminal
(only on Windows 10 and later; on earlier Windows systems, such sequences do
not work regardless of the setting of -Da).
-e or --quit-at-eof
Causes less to automatically exit the second time it reaches end-of-file. By de‐
fault, the only way to exit less is via the "q" command.
-E or --QUIT-AT-EOF
Causes less to automatically exit the first time it reaches end-of-file.
-f or --force
Forces non-regular files to be opened. (A non-regular file is a directory or a de‐
vice special file.) Also suppresses the warning message when a binary file is
opened. By default, less will refuse to open non-regular files. Note that some
operating systems will not allow directories to be read, even if -f is set.
-F or --quit-if-one-screen
Causes less to automatically exit if the entire file can be displayed on the first
screen. Also see the description of the LESS_SHELL_LINES environment variable be‐
low.
-g or --hilite-search
Normally, less will highlight ALL strings which match the last search command. The
-g option changes this behavior to highlight only the particular string which was
found by the last search command. This can cause less to run somewhat faster than
the default.
-G or --HILITE-SEARCH
The -G option suppresses all highlighting of strings found by search commands.
-hn or --max-back-scroll=n
Specifies a maximum number of lines to scroll backward. If it is necessary to
scroll backward more than n lines, the screen is repainted in a forward direction
instead. (If the terminal does not have the ability to scroll backward, -h0 is im‐
plied.)
-i or --ignore-case
Causes searches to ignore case; that is, uppercase and lowercase are considered
identical. This option is ignored if any uppercase letters appear in the search
pattern; in other words, if a pattern contains uppercase letters, then that search
does not ignore case.
-I or --IGNORE-CASE
Like -i, but searches ignore case even if the pattern contains uppercase letters.
-jn or --jump-target=n
Specifies a line on the screen where the "target" line is to be positioned. The
target line is the line specified by any command to search for a pattern, jump to a
line number, jump to a file percentage or jump to a tag. The screen line may be
specified by a number: the top line on the screen is 1, the next is 2, and so on.
The number may be negative to specify a line relative to the bottom of the screen:
the bottom line on the screen is -1, the second to the bottom is -2, and so on.
Alternately, the screen line may be specified as a fraction of the height of the
screen, starting with a decimal point: .5 is in the middle of the screen, .3 is
three tenths down from the first line, and so on. If the line is specified as a
fraction, the actual line number is recalculated if the terminal window is resized.
If the --header option is used and the target line specified by -j would be ob‐
scured by the header, the target line is moved to the first line after the header.
If any form of the -j option is used, repeated forward searches (invoked with "n"
or "N") begin at the line immediately after the target line, and repeated backward
searches begin at the target line, unless changed by -a or -A. For example, if
"-j4" is used, the target line is the fourth line on the screen, so forward search‐
es begin at the fifth line on the screen. However nonrepeated searches (invoked
with "/" or "?") always begin at the start or end of the current screen respec‐
tively.
-J or --status-column
Displays a status column at the left edge of the screen. The character displayed
in the status column may be one of:
> The line is chopped with the -S option, and the text that is chopped off be‐
yond the right edge of the screen contains a match for the current search.
< The line is horizontally shifted, and the text that is shifted beyond the
left side of the screen contains a match for the current search.
= The line is both chopped and shifted, and there are matches beyond both
sides of the screen.
* There are matches in the visible part of the line but none to the right or
left of it.
a-z, A-Z
The line has been marked with the corresponding letter via the m or M com‐
mand.
-kfilename or --lesskey-file=filename
Causes less to open and interpret the named file as a lesskey(1) binary file. Mul‐
tiple -k options may be specified. If the LESSKEY or LESSKEY_SYSTEM environment
variable is set, or if a lesskey file is found in a standard place (see KEY BIND‐
INGS), it is also used as a lesskey file. Note the warning under "--lesskey-con‐
tent" below.
--lesskey-src=filename
Causes less to open and interpret the named file as a lesskey(1) source file. If
the LESSKEYIN or LESSKEYIN_SYSTEM environment variable is set, or if a lesskey
source file is found in a standard place (see KEY BINDINGS), it is also used as a
lesskey source file. Prior to version 582, the lesskey program needed to be run to
convert a lesskey source file to a lesskey binary file for less to use. Newer ver‐
sions of less read the lesskey source file directly and ignore the binary file if
the source file exists. Note the warning under "--lesskey-content" below.
--lesskey-content=text
Causes less to interpret the specified text as the contents of a lesskey(1) source
file. In the text, lesskey lines may be separated by either newlines as usual, or
by semicolons. A literal semicolon may be represented by a backslash followed by a
semicolon.
Warning: certain environment variables such as LESS, LESSSECURE, LESSCHARSET and
others, which are used early in startup, cannot be set in a file specified by a
command line option (--lesskey, --lesskey-src or --lesskey-content). When using a
lesskey file to set environment variables, it is safer to use the default lesskey
file, or to specify the file using the LESSKEYIN or LESSKEY_CONTENT environment
variables rather than using a command line option.
-K or --quit-on-intr
Causes less to exit immediately (with status 2) when an interrupt character (usual‐
ly ^C) is typed. Normally, an interrupt character causes less to stop whatever it
is doing and return to its command prompt. Note that use of this option makes it
impossible to return to the command prompt from the "F" command.
-L or --no-lessopen
Ignore the LESSOPEN environment variable (see the INPUT PREPROCESSOR section be‐
low). This option can be set from within less, but it will apply only to files
opened subsequently, not to the file which is currently open.
-m or --long-prompt
Causes less to prompt verbosely (like more(1)), with the percent into the file. By
default, less prompts with a colon.
-M or --LONG-PROMPT
Causes less to prompt even more verbosely than more(1).
-n or --line-numbers
Suppresses line numbers. The default (to use line numbers) may cause less to run
more slowly in some cases, especially with a very large input file. Using line
numbers means: the line number will be displayed in the verbose prompt and in the =
command, and the v command will pass the current line number to the editor (see al‐
so the discussion of LESSEDIT in PROMPTS below).
-N or --LINE-NUMBERS
Causes a line number to be displayed at the beginning of each line in the display.
-ofilename or --log-file=filename
Causes less to copy its input to the named file as it is being viewed. This ap‐
plies only when the input file is a pipe, not an ordinary file. If the file al‐
ready exists, less will ask for confirmation before overwriting it.
-Ofilename or --LOG-FILE=filename
The -O option is like -o, but it will overwrite an existing file without asking for
confirmation.
If no log file has been specified, the -o and -O options can be used from within
less to specify a log file. Without a file name, they will simply report the name
of the log file. The "s" command is equivalent to specifying -o from within less.
-ppattern or --pattern=pattern
The -p option on the command line is equivalent to specifying +/pattern; that is,
it tells less to start at the first occurrence of pattern in the file.
-Pprompt or --prompt=prompt
Provides a way to tailor the three prompt styles to your own preference. This op‐
tion would normally be put in the LESS environment variable, rather than being
typed in with each less command. Such an option must either be the last option in
the LESS variable, or be terminated by a dollar sign.
-Ps followed by a string changes the default (short) prompt to that string.
-Pm changes the medium (-m) prompt.
-PM changes the long (-M) prompt.
-Ph changes the prompt for the help screen.
-P= changes the message printed by the = command.
-Pw changes the message printed while waiting for data (in the "F" command).
All prompt strings consist of a sequence of letters and special escape sequences.
See the section on PROMPTS for more details.
-q or --quiet or --silent
Causes moderately "quiet" operation: the terminal bell is not rung if an attempt is
made to scroll past the end of the file or before the beginning of the file. If
the terminal has a "visual bell", it is used instead. The bell will be rung on
certain other errors, such as typing an invalid character. The default is to ring
the terminal bell in all such cases.
-Q or --QUIET or --SILENT
Causes totally "quiet" operation: the terminal bell is never rung. If the terminal
has a "visual bell", it is used in all cases where the terminal bell would have
been rung.
-r or --raw-control-chars
Causes "raw" control characters to be displayed. The default is to display control
characters using the caret notation; for example, a control-A (octal 001) is dis‐
played as "^A" (with some exceptions as described under the -U option). Warning:
when the -r option is used, less cannot keep track of the actual appearance of the
screen (since this depends on how the screen responds to each type of control char‐
acter). Thus, various display problems may result, such as long lines being split
in the wrong place.
USE OF THE -r OPTION IS DANGEROUS AND IS NOT RECOMMENDED.
The -r option can be set on the command line or via the - command, but to avoid un‐
intentional use, it cannot be set in a LESS environment variable. If -r appears in
a LESS environment variable, it is treated as if it were -R.
-R or --RAW-CONTROL-CHARS
Like -r, but only a limited set of escape sequences are output in "raw" form. Un‐
like -r, the screen appearance is maintained correctly. The sequences which are
output raw are:
1. ANSI SGR ("color") sequences
2. OSC 8 hyperlinks
3. Other OSC sequences, if the OSC type number is listed in the LESSANSIOSCALLOW
environment variable
4. OSC sequences starting with a non-standard introductory character (that is,
something other than "]"), if the character is listed in the LESSANSIOSCCHARS envi‐
ronment variable followed by an asterisk
ANSI color escape sequences are sequences of the form:
ESC [ ... m
where the "..." is zero or more color specification characters. Color escape se‐
quences are only supported when the color is changed within one line, not across
lines. In other words, the beginning of each line is assumed to be normal (non-
colored), regardless of any escape sequences in previous lines.
You can make less think that characters other than "m" can end ANSI color escape
sequences by setting the environment variable LESSANSIENDCHARS to the list of char‐
acters which can end a color escape sequence. And you can make less think that
characters other than the standard ones may appear between the ESC and the m by
setting the environment variable LESSANSIMIDCHARS to the list of characters which
can appear.
OSC sequences are of the form:
ESC ] N ; ... \7
where the OSC type number N is a decimal integer. The terminating sequence may be
either a BEL character (\7) as above, or the two-character sequence "ESC \".
-s or --squeeze-blank-lines
Causes consecutive blank lines to be squeezed into a single blank line. This is
useful when viewing nroff(1) output.
-S or --chop-long-lines
Causes lines longer than the screen width to be chopped (truncated) rather than
wrapped. That is, the portion of a long line that does not fit in the screen width
is not displayed until you press RIGHT-ARROW. The default is to wrap long lines;
that is, display the remainder on the next line. See also the --wordwrap option.
While the --header option is active, the -S option is ignored, and lines longer
than the screen width are truncated.
-ttag or --tag=tag
The -t option, followed immediately by a TAG, will edit the file containing that
tag. For this to work, tag information must be available; for example, there may
be a file in the current directory called "tags", which was previously built by
ctags(1) or an equivalent command. If the environment variable LESSGLOBALTAGS is
set, it is taken to be the name of a command compatible with global(1), and that
command is executed to find the tag. (See
http://www.gnu.org/software/global/global.html). The -t option may also be speci‐
fied from within less (using the - command) as a way of examining a new file. The
command ":t" is equivalent to specifying -t from within less.
-Ttagsfile or --tag-file=tagsfile
Specifies a tags file to be used instead of "tags".
-u or --underline-special
Causes backspaces and carriage returns to be treated as printable characters; that
is, they are sent to the terminal when they appear in the input.
-U or --UNDERLINE-SPECIAL
Causes backspaces, tabs, carriage returns and "formatting characters" (as defined
by Unicode) to be treated as control characters; that is, they are handled as spec‐
ified by the -r option.
By default, if neither -u nor -U is given, backspaces which appear adjacent to an
underscore character are treated specially: the underlined text is displayed using
the terminal's hardware underlining capability. Also, backspaces which appear be‐
tween two identical characters are treated specially: the overstruck text is print‐
ed using the terminal's hardware boldface capability. Other backspaces are delet‐
ed, along with the preceding character. Carriage returns immediately followed by a
newline are deleted. Other carriage returns are handled as specified by the -r op‐
tion. Unicode formatting characters, such as the Byte Order Mark, are sent to the
terminal. Text which is overstruck or underlined can be searched for if neither -u
nor -U is in effect.
See also the --proc-backspace, --proc-tab, and --proc-return options.
-V or --version
Displays the version number of less.
-w or --hilite-unread
Temporarily highlights the first "new" line after a forward movement of a full
page. The first "new" line is the line immediately following the line previously
at the bottom of the screen. Also highlights the target line after a g or p com‐
mand. The highlight is removed at the next command which causes movement. If the
--status-line option is in effect, the entire line (the width of the screen) is
highlighted. Otherwise, only the text in the line is highlighted, unless the -J
option is in effect, in which case only the status column is highlighted.
-W or --HILITE-UNREAD
Like -w, but temporarily highlights the first new line after any forward movement
command larger than one line.
-xn,... or --tabs=n,...
Sets tab stops. If only one n is specified, tab stops are set at multiples of n.
If multiple values separated by commas are specified, tab stops are set at those
positions, and then continue with the same spacing as the last two. For example,
"-x9,17" will set tabs at positions 9, 17, 25, 33, etc. The default for n is 8.
-X or --no-init
Disables sending the termcap initialization and deinitialization strings to the
terminal. This is sometimes desirable if the deinitialization string does some‐
thing unnecessary, like clearing the screen.
-yn or --max-forw-scroll=n
Specifies a maximum number of lines to scroll forward. If it is necessary to
scroll forward more than n lines, the screen is repainted instead. The -c or -C
option may be used to repaint from the top of the screen if desired. By default,
any forward movement causes scrolling.
-zn or --window=n or -n
Changes the default scrolling window size to n lines. The default is one screen‐
ful. The z and w commands can also be used to change the window size. The "z" may
be omitted for compatibility with some versions of more(1). If the number n is
negative, it indicates n lines less than the current screen size. For example, if
the screen is 24 lines, -z-4 sets the scrolling window to 20 lines. If the screen
is resized to 40 lines, the scrolling window automatically changes to 36 lines.
-"cc or --quotes=cc
Changes the filename quoting character. This may be necessary if you are trying to
name a file which contains both spaces and quote characters. Followed by a single
character, this changes the quote character to that character. Filenames contain‐
ing a space should then be surrounded by that character rather than by double
quotes. Followed by two characters, changes the open quote to the first character,
and the close quote to the second character. Filenames containing a space should
then be preceded by the open quote character and followed by the close quote char‐
acter. Note that even after the quote characters are changed, this option remains
-" (a dash followed by a double quote).
-~ or --tilde
Normally lines after end of file are displayed as a single tilde (~). This option
causes lines after end of file to be displayed as blank lines.
-# or --shift
Specifies the default number of positions to scroll horizontally in the RIGHTARROW
and LEFTARROW commands. If the number specified is zero, it sets the default num‐
ber of positions to one half of the screen width. Alternately, the number may be
specified as a fraction of the width of the screen, starting with a decimal point:
.5 is half of the screen width, .3 is three tenths of the screen width, and so on.
If the number is specified as a fraction, the actual number of scroll positions is
recalculated if the terminal window is resized.
--cmd=commands
The specified string is taken to be an initial command to less. This is similar to
specifying "+commands", except that commands specified by --cmd are not executed if
less exits immediately due to the use of the -E or -F option, while commands speci‐
fied by the + option are executed even if less exits immediately.
--exit-follow-on-close
When using the "F" command on a pipe, less will automatically stop waiting for more
data when the input side of the pipe is closed.
--file-size
If --file-size is specified, less will determine the size of the file immediately
after opening the file. Then the "=" command will display the number of lines in
the file. Normally this is not done, because it can be slow if the input file is
non-seekable (such as a pipe) and is large.
--follow-name
Normally, if the input file is renamed while an F command is executing, less will
continue to display the contents of the original file despite its name change. If
--follow-name is specified, during an F command less will periodically attempt to
reopen the file by name. If the reopen succeeds and the file is a different file
from the original (which means that a new file has been created with the same name
as the original (now renamed) file), less will display the contents of that new
file.
--form-feed
When scrolling forward or backward in the file, stop if a line beginning with a
form feed character (^L) is reached. This can be useful when viewing a file which
uses form feeds between pages.
--header=L,C,N
Sets the number of header lines and columns displayed on the screen. The number of
header lines is set to L. If L is 0, header lines are disabled. If L is empty or
missing, the number of header lines is unchanged. The number of header columns is
set to C. If C is 0, header columns are disabled. If C is empty or missing, the
number of header columns is unchanged. The first header line is set to line number
N in the file. If N is empty or missing, it is taken to be the number of the line
currently displayed in the first line of the screen (if the --header command has
been issued from within less), or 1 (if the --header option has been given on the
command line). The special form "--header=-" disables header lines and header
columns, and is equivalent to "--header=0,0".
When L is nonzero, the first L lines at the top of the screen are replaced with the
L lines of the file beginning at line N, regardless of what part of the file is be‐
ing viewed. When header lines are displayed, any file contents before the header
line cannot be viewed. When C is nonzero, the first C characters displayed at the
beginning of each line are replaced with the first C characters of the line, even
if the rest of the line is scrolled horizontally.
While the --header option is active, lines longer than the screen width are trun‐
cated, and the -S option is ignored.
--incsearch
Subsequent search commands will be "incremental"; that is, less will advance to the
next line containing the search pattern as each character of the pattern is typed
in.
--intr=c
Use the character c instead of ^X to interrupt a read when the "Waiting for data"
message is displayed. c must be an ASCII character; that is, one with a value be‐
tween 1 and 127 inclusive. A caret followed by a single character can be used to
specify a control character.
--line-num-width=n
Sets the minimum width of the line number field when the -N option is in effect to
n characters. The default is 7.
--match-shift=n
When -S is in effect, if a search match is not visible because it is shifted to the
left or right of the currently visible screen, the text will horizontally shift to
ensure that the search match is visible. This option selects the column in which
the first character of the search match will be placed after the shift. In other
words, there will be n characters visible to the left of the search match.
Alternately, the number may be specified as a fraction of the width of the screen,
starting with a decimal point: .5 is half of the screen width, .3 is three tenths
of the screen width, and so on. If the number is specified as a fraction, the ac‐
tual number of scroll positions is recalculated if the terminal window is resized.
--modelines=n
Before displaying a file, less will read the first n lines to try to find a vim-
compatible modeline. If n is zero, less does not try to find modelines. By using
a modeline, the file itself can specify the tab stops that should be used when
viewing it.
A modeline contains, anywhere in the line, a program name ("vi", "vim", "ex", or
"less"), followed by a colon, possibly followed by the word "set", and finally fol‐
lowed by zero or more option settings. If the word "set" is used, option settings
are separated by spaces, and end at the first colon. If the word "set" is not
used, option settings may be separated by either spaces or colons. The word "set"
is required if the program name is "less" but optional if any of the other three
names are used. If any option setting is of the form "tabstop=n" or "ts=n", then
tab stops are automatically set as if --tabs=n had been given. See the --tabs de‐
scription for acceptable values of n.
--mouse
Enables mouse input: scrolling the mouse wheel down moves forward in the file,
scrolling the mouse wheel up moves backwards in the file, left-click sets the "#"
mark to the line where the mouse is clicked, and right-click (or any other) returns
to the "#" mark position. Holding down the left button and dragging also moves in
the file. If a left-click is performed with the mouse cursor on an OSC 8 hyper‐
link, the hyperlink is selected as if by the ^O^N command. If a left-click is per‐
formed with the mouse cursor on an OSC 8 hyperlink which is already selected, the
hyperlink is opened as if by the ^O^O command. The number of lines to scroll when
the wheel is moved can be set by the --wheel-lines option. Mouse input works only
on terminals which support X11 mouse reporting, and on the Windows version of less.
--MOUSE
Like --mouse, except the direction scrolled on mouse wheel movement is reversed.
--no-edit-warn
Don't print a warning message when using the v command on a file which was opened
using a LESSOPEN preprocessor (see the INPUT PREPROCESSOR section below).
--no-keypad
Disables sending the keypad initialization and deinitialization strings to the ter‐
minal. This is sometimes useful if the keypad strings make the numeric keypad be‐
have in an undesirable manner.
--no-histdups
This option changes the behavior so that if a search string or file name is typed
in, and the same string is already in the history list, the existing copy is re‐
moved from the history list before the new one is added. Thus, a given string will
appear only once in the history list. Normally, a string may appear multiple
times.
--no-number-headers
Header lines (defined via the --header option) are not assigned line numbers. Line
number 1 is assigned to the first line after any header lines.
--no-paste
If the terminal supports xterm-compatible "bracketed paste", any text pasted into
less is ignored, except that one line of text may be pasted into the command line
at the bottom of the screen (search strings, file names, etc). That is, the first
newline of text pasted into the command line and any text that follows it is ig‐
nored.
--no-search-header-lines
Searches do not include header lines, but still include header columns.
--no-search-header-columns
Searches do not include header columns, but still include header lines.
--no-search-headers
Searches do not include header lines or header columns.
--no-vbell
Disables the terminal's visual bell.
--proc-backspace
If set, backspaces are handled as if neither the -u option nor the -U option were
set. That is, a backspace adjacent to an underscore causes text to be displayed in
underline mode, and a backspace between identical characters cause text to be dis‐
played in boldface mode. This option overrides the -u and -U options, so that dis‐
play of backspaces can be controlled separate from tabs and carriage returns. If
not set, backspace display is controlled by the -u and -U options.
--PROC-BACKSPACE
If set, backspaces are handled as if the -U option were set; that is backspaces are
treated as control characters.
--proc-return
If set, carriage returns are handled as if neither the -u option nor the -U option
were set. That is, a carriage return immediately before a newline is deleted.
This option overrides the -u and -U options, so that display of carriage returns
can be controlled separate from that of backspaces and tabs. If not set, carriage
return display is controlled by the -u and -U options.
--PROC-RETURN
If set, carriage returns are handled as if the -U option were set; that is carriage
returns are treated as control characters.
--proc-tab
If set, tabs are handled as if the -U option were not set. That is, tabs are ex‐
panded to spaces. This option overrides the -U option, so that display of tabs can
be controlled separate from that of backspaces and carriage returns. If not set,
tab display is controlled by the -U option.
--PROC-TAB
If set, tabs are handled as if the -U option were set; that is tabs are treated as
control characters.
--redraw-on-quit
When quitting, after sending the terminal deinitialization string, redraws the en‐
tire last screen. On terminals whose terminal deinitialization string causes the
terminal to switch from an alternate screen, this makes the last screenful of the
current file remain visible after less has quit.
--rscroll=c
This option changes the character used to mark truncated lines. It may begin with
a two-character attribute indicator like LESSBINFMT does. If there is no attribute
indicator, standout is used. If set to "-", truncated lines are not marked.
--save-marks
Save marks in the history file, so marks are retained across different invocations
of less.
--search-options=...
Sets default search modifiers. The value is a string of one or more of the charac‐
ters E, F, K, N, R or W. Setting any of these has the same effect as typing that
control character at the beginning of every search pattern. For example, setting
--search-options=W is the same as typing ^W at the beginning of every pattern. The
value may also contain a digit between 1 and 5, which has the same effect as typing
^S followed by that digit at the beginning of every search pattern. The value "-"
disables all default search modifiers.
--show-preproc-errors
If a preprocessor produces data, then exits with a non-zero exit code, less will
display a warning.
--status-col-width=n
Sets the width of the status column when the -J option is in effect. The default
is 2 characters.
--status-line
If a line is marked, the entire line (rather than just the status column) is high‐
lighted. Also lines highlighted due to the -w option will have the entire line
highlighted. If --use-color is set, the line is colored rather than highlighted.
--use-backslash
This option changes the interpretations of options which follow this one. After
the --use-backslash option, any backslash in an option string is removed and the
following character is taken literally. This allows a dollar sign to be included
in option strings.
--use-color
Enables colored text in various places. The -D option can be used to change the
colors. Colored text works only if the terminal supports ANSI color escape se‐
quences (as defined in https://www.ecma-international.org/publications-and-
standards/standards/ecma-48).
--wheel-lines=n
Set the number of lines to scroll when the mouse wheel is scrolled and the --mouse
or --MOUSE option is in effect. The default is 1 line.
--wordwrap
When the -S option is not in use, wrap each line at a space or tab if possible, so
that a word is not split between two lines. The default is to wrap at any charac‐
ter.
-- A command line argument of "--" marks the end of option arguments. Any arguments
following this are interpreted as filenames. This can be useful when viewing a
file whose name begins with a "-" or "+". Otherwise, option arguments and filename
arguments can be intermixed; that is, option arguments do not need to appear before
filename arguments, unless the environment variable POSIXLY_CORRECT is set.
+ If a command line option begins with +, the remainder of that option is taken to be
an initial command to less. For example, +G tells less to start at the end of the
file rather than the beginning, and +/xyz tells it to start at the first occurrence
of "xyz" in the file. As a special case, +<number> acts like +<number>g; that is,
it starts the display at the specified line number (however, see the caveat under
the "g" command above). If the option starts with ++, the initial command applies
to every file being viewed, not just the first one. The + command described previ‐
ously may also be used to set (or change) an initial command for every file. Also
see the --cmd option.
LINE EDITING
When entering a command line at the bottom of the screen (for example, a filename for the
:e command, or the pattern for a search command), certain keys can be used to manipulate
the command line. Most commands have an alternate form in [ brackets ] which can be used
if a key does not exist on a particular keyboard. (Note that the forms beginning with ESC
do not work on some MS-DOS and Windows systems because ESC is the line erase character.)
Any of these special keys may be entered literally by preceding it with the "literal"
character, either ^V or ^A. A backslash itself may also be entered literally by entering
two backslashes.
LEFTARROW [ ESC-h ]
Move the cursor one space to the left.
RIGHTARROW [ ESC-l ]
Move the cursor one space to the right.
^LEFTARROW [ ESC-b or ESC-LEFTARROW ]
(That is, CONTROL and LEFTARROW simultaneously.) Move the cursor one word to the
left.
^RIGHTARROW [ ESC-w or ESC-RIGHTARROW ]
(That is, CONTROL and RIGHTARROW simultaneously.) Move the cursor one word to the
right.
HOME [ ESC-0 ]
Move the cursor to the beginning of the line.
END [ ESC-$ ]
Move the cursor to the end of the line.
BACKSPACE
Delete the character to the left of the cursor, or cancel the command if the com‐
mand line is empty.
DELETE or [ ESC-x ]
Delete the character under the cursor.
^BACKSPACE [ ESC-BACKSPACE ]
(That is, CONTROL and BACKSPACE simultaneously.) Delete the word to the left of
the cursor.
^DELETE [ ESC-X or ESC-DELETE ]
(That is, CONTROL and DELETE simultaneously.) Delete the word under the cursor.
UPARROW [ ESC-k ]
Retrieve the previous command line. If you first enter some text and then press
UPARROW, it will retrieve the previous command which begins with that text.
DOWNARROW [ ESC-j ]
Retrieve the next command line. If you first enter some text and then press DOW‐
NARROW, it will retrieve the next command which begins with that text.
TAB Complete the partial filename to the left of the cursor. If it matches more than
one filename, the first match is entered into the command line. Repeated TABs will
cycle thru the other matching filenames. If the completed filename is a directory,
a "/" is appended to the filename. (On MS-DOS and Windows systems, a "\" is ap‐
pended.) The environment variable LESSSEPARATOR can be used to specify a different
character to append to a directory name.
BACKTAB [ ESC-TAB ]
Like, TAB, but cycles in the reverse direction thru the matching filenames.
^L Complete the partial filename to the left of the cursor. If it matches more than
one filename, all matches are entered into the command line (if they fit).
^U (Unix and OS/2) or ESC (MS-DOS and Windows)
Delete the entire command line, or cancel the command if the cursor is at the be‐
ginning of the command line. If you have changed your line-kill character in Unix
to something other than ^U, that character is used instead of ^U.
^G Delete the entire command line and return to the main prompt.
KEY BINDINGS
You may define your own less commands by creating a lesskey source file. This file speci‐
fies a set of command keys and an action associated with each key. You may also change
the line-editing keys (see LINE EDITING), and set environment variables used by less. See
the lesskey(1) manual page for details about the file format.
If the environment variable LESSKEYIN is set, less uses that as the name of the lesskey
source file. Otherwise, less looks in a standard place for the lesskey source file: On
Unix systems, less looks for a lesskey file called "$XDG_CONFIG_HOME/lesskey" or
"$HOME/.config/lesskey" or "$HOME/.lesskey". On MS-DOS and Windows systems, less looks
for a lesskey file called "$HOME/_lesskey", and if it is not found there, then looks for a
lesskey file called "_lesskey" in any directory specified in the PATH environment vari‐
able. On OS/2 systems, less looks for a lesskey file called "$HOME/lesskey.ini", and if
it is not found, then looks for a lesskey file called "lesskey.ini" in any directory spec‐
ified in the INIT environment variable, and if it not found there, then looks for a
lesskey file called "lesskey.ini" in any directory specified in the PATH environment vari‐
able.
A system-wide lesskey source file may also be set up to provide key bindings. If a key is
defined in both a local lesskey file and in the system-wide file, key bindings in the lo‐
cal file take precedence over those in the system-wide file. If the environment variable
LESSKEYIN_SYSTEM is set, less uses that as the name of the system-wide lesskey file. Oth‐
erwise, less looks in a standard place for the system-wide lesskey file: On Unix systems,
the system-wide lesskey file is /usr/local/etc/syslesskey. (However, if less was built
with a different sysconf directory than /usr/local/etc, that directory is where the sys‐
less file is found.) On MS-DOS and Windows systems, the system-wide lesskey file is
c:\_syslesskey. On OS/2 systems, the system-wide lesskey file is c:\syslesskey.ini.
Older versions of less (before v582) used lesskey files with a binary format, produced by
the lesskey program. It is no longer necessary to use the lesskey program.
INPUT PREPROCESSOR
You may define an "input preprocessor" for less. Before less opens a file, it first gives
the input preprocessor a chance to modify the way the contents of the file are displayed.
An input preprocessor is simply an executable program (or shell script), which writes the
contents of the file to a different file, called the replacement file. The contents of
the replacement file are then displayed in place of the contents of the original file.
However, it will appear to the user as if the original file is opened; that is, less will
display the original filename as the name of the current file.
An input preprocessor receives one command line argument, the original filename, as en‐
tered by the user. It should create the replacement file, and when finished, print the
name of the replacement file to its standard output. If the input preprocessor does not
output a replacement filename, less uses the original file, as normal. The input pre‐
processor is not called when viewing standard input. To set up an input preprocessor, set
the LESSOPEN environment variable to a command line which will invoke your input pre‐
processor. This command line should include one occurrence of the string "%s", which will
be replaced by the filename when the input preprocessor command is invoked.
When less closes a file opened in such a way, it will call another program, called the in‐
put postprocessor, which may perform any desired clean-up action (such as deleting the re‐
placement file created by LESSOPEN). This program receives two command line arguments,
the original filename as entered by the user, and the name of the replacement file. To
set up an input postprocessor, set the LESSCLOSE environment variable to a command line
which will invoke your input postprocessor. It may include two occurrences of the string
"%s"; the first is replaced with the original name of the file and the second with the
name of the replacement file, which was output by LESSOPEN.
For example, on many Unix systems, these two scripts will allow you to keep files in com‐
pressed format, but still let less view them directly:
lessopen.sh:
#! /bin/sh
case "$1" in
*.Z) TEMPFILE=$(mktemp)
uncompress -c $1 >$TEMPFILE 2>/dev/null
if [ -s $TEMPFILE ]; then
echo $TEMPFILE
else
rm -f $TEMPFILE
fi
;;
esac
lessclose.sh:
#! /bin/sh
rm $2
To use these scripts, put them both where they can be executed and set
LESSOPEN="lessopen.sh %s", and LESSCLOSE="lessclose.sh %s %s". More complex LESSOPEN and
LESSCLOSE scripts may be written to accept other types of compressed files, and so on.
It is also possible to set up an input preprocessor to pipe the file data directly to
less, rather than putting the data into a replacement file. This avoids the need to de‐
compress the entire file before starting to view it. An input preprocessor that works
this way is called an input pipe. An input pipe, instead of writing the name of a re‐
placement file on its standard output, writes the entire contents of the replacement file
on its standard output. If the input pipe does not write any characters on its standard
output, then there is no replacement file and less uses the original file, as normal. To
use an input pipe, make the first character in the LESSOPEN environment variable a verti‐
cal bar (|) to signify that the input preprocessor is an input pipe. As with non-pipe in‐
put preprocessors, the command string must contain one occurrence of %s, which is replaced
with the filename of the input file.
For example, on many Unix systems, this script will work like the previous example
scripts:
lesspipe.sh:
#! /bin/sh
case "$1" in
*.Z) uncompress -c $1 2>/dev/null
;;
*) exit 1
;;
esac
exit $?
To use this script, put it where it can be executed and set LESSOPEN="|lesspipe.sh %s".
Note that a preprocessor cannot output an empty file, since that is interpreted as meaning
there is no replacement, and the original file is used. To avoid this, if LESSOPEN starts
with two vertical bars, the exit status of the script determines the behavior when the
output is empty. If the output is empty and the exit status is zero, the empty output is
considered to be replacement text. If the output is empty and the exit status is nonzero,
the original file is used. For compatibility with previous versions of less, if LESSOPEN
starts with only one vertical bar, the exit status of the preprocessor is ignored.
When an input pipe is used, a LESSCLOSE postprocessor can be used, but it is usually not
necessary since there is no replacement file to clean up. In this case, the replacement
file name passed to the LESSCLOSE postprocessor is "-".
For compatibility with previous versions of less, the input preprocessor or pipe is not
used if less is viewing standard input. However, if the first character of LESSOPEN is a
dash (-), the input preprocessor is used on standard input as well as other files. In
this case, the dash is not considered to be part of the preprocessor command. If standard
input is being viewed, the input preprocessor is passed a file name consisting of a single
dash. Similarly, if the first two characters of LESSOPEN are vertical bar and dash (|-)
or two vertical bars and a dash (||-), the input pipe is used on standard input as well as
other files. Again, in this case the dash is not considered to be part of the input pipe
command.
NATIONAL CHARACTER SETS
There are five types of characters in the input file:
normal characters
can be displayed directly to the screen.
control characters
should not be displayed directly, but are expected to be found in ordinary text
files (such as backspace and tab).
binary characters
should not be displayed directly and are not expected to be found in text files.
composing characters
are not displayed separately, but modify the display of the preceding character.
(Only when LESSCHARSET is "utf8".)
deleted characters
are simply deleted from the input and not displayed. (Only when LESSCHARSET is
"utf8".)
A "character set" is simply a description of which characters are to be considered normal,
control, and binary. The LESSCHARSET environment variable may be used to select a charac‐
ter set. Possible values for LESSCHARSET are:
ascii BS, TAB, NL, CR, and formfeed are control characters, all chars with values between
32 and 126 are normal, and all others are binary.
iso8859
Selects an ISO 8859 character set. This is the same as ASCII, except characters
between 160 and 255 are treated as normal characters.
latin1 Same as iso8859.
latin9 Same as iso8859.
dos Selects a character set appropriate for MS-DOS.
ebcdic Selects an EBCDIC character set.
IBM-1047
Selects an EBCDIC character set used by OS/390 Unix Services. This is the EBCDIC
analogue of latin1. You get similar results by setting either LESSCHARSET=IBM-1047
or LC_CTYPE=en_US in your environment.
koi8-r Selects a Russian character set.
next Selects a character set appropriate for NeXT computers.
utf-8 Selects the UTF-8 encoding of the ISO 10646 character set. UTF-8 is special in
that it supports multi-byte characters in the input file. It is the only character
set that supports multi-byte characters.
windows
Selects a character set appropriate for Microsoft Windows (cp 1252).
In rare cases, it may be desired to tailor less to use a character set other than the ones
definable by LESSCHARSET. In this case, the environment variable LESSCHARDEF can be used
to define a character set. It should be set to a string where each character in the
string represents one character in the character set. The character "." is used for a
normal character, "c" for control, and "b" for binary. A decimal number may be used for
repetition. For example, "bccc4b." would mean character 0 is binary, 1, 2 and 3 are con‐
trol, 4, 5, 6 and 7 are binary, and 8 is normal. All characters after the last are taken
to be the same as the last, so characters 9 through 255 would be normal. (This is an ex‐
ample, and does not necessarily represent any real character set.)
This table shows the value of LESSCHARDEF which is equivalent to each of the possible val‐
ues for LESSCHARSET:
ascii 8bcccbcc18b95.b
dos 8bcccbcc12bc5b95.b.
ebcdic 5bc6bcc7bcc41b.9b7.9b5.b..8b6.10b6.b9.7b
9.8b8.17b3.3b9.7b9.8b8.6b10.b.b.b.
IBM-1047 4cbcbc3b9cbccbccbb4c6bcc5b3cbbc4bc4bccbc
191.b
iso8859 8bcccbcc18b95.33b.
koi8-r 8bcccbcc18b95.b128.
latin1 8bcccbcc18b95.33b.
next 8bcccbcc18b95.bb125.bb
If neither LESSCHARSET nor LESSCHARDEF is set, but any of the strings "UTF-8", "UTF8",
"utf-8" or "utf8" is found in the LC_ALL, LC_CTYPE or LANG environment variables, then the
default character set is utf-8.
If that string is not found, but your system supports the setlocale interface, less will
use setlocale to determine the character set. setlocale is controlled by setting the LANG
or LC_CTYPE environment variables.
Finally, if the setlocale interface is also not available, the default character set is
utf-8.
Control and binary characters are displayed in standout (reverse video). Each such char‐
acter is displayed in caret notation if possible (e.g. ^A for control-A). Caret notation
is used only if inverting the 0100 bit results in a normal printable character. Other‐
wise, the character is displayed as a hex number in angle brackets. This format can be
changed by setting the LESSBINFMT environment variable. LESSBINFMT may begin with a "*"
and one character to select the display attribute: "*k" is blinking, "*d" is bold, "*u" is
underlined, "*s" is standout, and "*n" is normal. If LESSBINFMT does not begin with a
"*", normal attribute is assumed. The remainder of LESSBINFMT is a string which may in‐
clude one printf-style escape sequence (a % followed by x, X, o, d, etc.). For example,
if LESSBINFMT is "*u[%x]", binary characters are displayed in underlined hexadecimal sur‐
rounded by brackets. The default if no LESSBINFMT is specified is "*s<%02X>". Warning:
the result of expanding the character via LESSBINFMT must be less than 31 characters.
When the character set is utf-8, the LESSUTFBINFMT environment variable acts similarly to
LESSBINFMT but it applies to Unicode code points that were successfully decoded but are
unsuitable for display (e.g., unassigned code points). Its default value is "<U+%04lX>".
Note that LESSUTFBINFMT and LESSBINFMT share their display attribute setting ("*x") so
specifying one will affect both; LESSUTFBINFMT is read after LESSBINFMT so its setting, if
any, will have priority. Problematic octets in a UTF-8 file (octets of a truncated se‐
quence, octets of a complete but non-shortest form sequence, invalid octets, and stray
trailing octets) are displayed individually using LESSBINFMT so as to facilitate diagnos‐
tic of how the UTF-8 file is ill-formed.
When the character set is utf-8, in rare cases it may be desirable to override the Unicode
definition of the type of certain characters. For example, characters in a Private Use
Area are normally treated as binary characters, but if you are using a custom font with
printable characters in that range, it may be desirable to tell less to treat such charac‐
ters as printable. This can be done by setting the LESSUTFCHARDEF environment variable to
a comma-separated list of character type definitions. Each character type definition con‐
sists of either one hexadecimal codepoint or a pair of codepoints separated by a dash,
followed by a colon and a type character. Each hexadecimal codepoint may optionally be
preceded by a "U" or "U+". If a pair of codepoints is given, the type is set for all
characters inclusively between the two values. If there are multiple comma-separated
codepoint values, they must be in ascending numerical order. The type character may be
one of:
p A normal printable character.
w A wide (2-space) printable character.
b A binary (non-printable) character.
c A composing (zero width) character.
d A deleted character (deleted from the input and not displayed).
For example, setting LESSUTFCHARDEF to
E000-F8FF:p,F0000-FFFFD:p,100000-10FFFD:p
would make all Private Use Area characters be treated as printable.
By default, emoji modifiers, components and variation selectors are deleted because many
terminals do not display them correctly. If you use a terminal which does display some or
all of them correctly, you can cause to be displayed by setting LESSUTFCHARDEF to treat
them as composing characters. For example, this sets them all to composing characters:
FE00-FE0F:c,1F3FB-1F3FF:c,1F9B0-1F9B3:c,E0100-E01EF:c
PROMPTS
The -P option allows you to tailor the prompt to your preference. The string given to the
-P option replaces the specified prompt string. Certain characters in the string are in‐
terpreted specially. The prompt mechanism is rather complicated to provide flexibility,
but the ordinary user need not understand the details of constructing personalized prompt
strings.
A percent sign followed by a single character is expanded according to what the following
character is. (References to the input file size below refer to the preprocessed size, if
an input preprocessor is being used.)
%bX Replaced by the byte offset into the current input file. The b is followed by a
single character (shown as X above) which specifies the line whose byte offset is
to be used. If the character is a "t", the byte offset of the top line in the dis‐
play is used, an "m" means use the middle line, a "b" means use the bottom line, a
"B" means use the line just after the bottom line, and a "j" means use the "target"
line, as specified by the -j option.
%B Replaced by the size of the current input file.
%c Replaced by the column number of the text appearing in the first column of the
screen.
%dX Replaced by the page number of a line in the input file. The line to be used is
determined by the X, as with the %b option.
%D Replaced by the number of pages in the input file, or equivalently, the page number
of the last line in the input file.
%E Replaced by the name of the editor (from the VISUAL environment variable, or the
EDITOR environment variable if VISUAL is not defined). See the discussion of the
LESSEDIT feature below.
%f Replaced by the name of the current input file.
%F Replaced by the last component of the name of the current input file.
%g Replaced by the shell-escaped name of the current input file. This is useful when
the expanded string will be used in a shell command, such as in LESSEDIT.
%i Replaced by the index of the current file in the list of input files.
%lX Replaced by the line number of a line in the input file. The line to be used is
determined by the X, as with the %b option.
%L Replaced by the line number of the last line in the input file.
%m Replaced by the total number of input files.
%o Replaced by the URI of the currently selected OSC 8 hyperlink, or a question mark
if no hyperlink is selected. This is used by OSC 8 handlers as explained in the
^O^O command description.
%pX Replaced by the percent into the current input file, based on byte offsets. The
line used is determined by the X as with the %b option.
%PX Replaced by the percent into the current input file, based on line numbers. The
line used is determined by the X as with the %b option.
%s Same as %B.
%t Causes any trailing spaces to be removed. Usually used at the end of the string,
but may appear anywhere.
%T Normally expands to the word "file". However if viewing files via a tags list us‐
ing the -t option, it expands to the word "tag".
%x Replaced by the name of the next input file in the list.
If any item is unknown (for example, the file size if input is a pipe), a question mark is
printed instead.
The format of the prompt string can be changed depending on certain conditions. A ques‐
tion mark followed by a single character acts like an "IF": depending on the following
character, a condition is evaluated. If the condition is true, any characters following
the question mark and condition character, up to a period, are included in the prompt. If
the condition is false, such characters are not included. A colon appearing between the
question mark and the period can be used to establish an "ELSE": any characters between
the colon and the period are included in the string if and only if the IF condition is
false. Condition characters (which follow a question mark) may be:
?a True if any characters have been included in the prompt so far.
?bX True if the byte offset of the specified line is known.
?B True if the size of current input file is known.
?c True if the text is horizontally shifted (%c is not zero).
?dX True if the page number of the specified line is known.
?e True if at end-of-file.
?f True if there is an input filename (that is, if input is not a pipe).
?lX True if the line number of the specified line is known.
?L True if the line number of the last line in the file is known.
?m True if there is more than one input file.
?n True if this is the first prompt in a new input file.
?pX True if the percent into the current input file, based on byte offsets, of the
specified line is known.
?PX True if the percent into the current input file, based on line numbers, of the
specified line is known.
?s Same as "?B".
?x True if there is a next input file (that is, if the current input file is not the
last one).
Any characters other than the special ones (question mark, colon, period, percent, and
backslash) become literally part of the prompt. Any of the special characters may be in‐
cluded in the prompt literally by preceding it with a backslash.
Some examples:
?f%f:Standard input.
This prompt prints the filename, if known; otherwise the string "Standard input".
?f%f .?ltLine %lt:?pt%pt\%:?btByte %bt:-...
This prompt would print the filename, if known. The filename is followed by the line num‐
ber, if known, otherwise the percent if known, otherwise the byte offset if known. Other‐
wise, a dash is printed. Notice how each question mark has a matching period, and how the
% after the %pt is included literally by escaping it with a backslash.
?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\: %x..%t
This prints the filename if this is the first prompt in a file, followed by the "file N of
N" message if there is more than one input file. Then, if we are at end-of-file, the
string "(END)" is printed followed by the name of the next file, if there is one. Final‐
ly, any trailing spaces are truncated. This is the default prompt. For reference, here
are the defaults for the other two prompts (-m and -M respectively). Each is broken into
two lines here for readability only.
?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\: %x.:
?pB%pB\%:byte %bB?s/%s...%t
?f%f .?n?m(%T %i of %m) ..?ltlines %lt-%lb?L/%L. :
byte %bB?s/%s. .?e(END) ?x- Next\: %x.:?pB%pB\%..%t
And here is the default message produced by the = command:
?f%f .?m(%T %i of %m) .?ltlines %lt-%lb?L/%L. .
byte %bB?s/%s. ?e(END) :?pB%pB\%..%t
The prompt expansion features are also used for another purpose: if an environment vari‐
able LESSEDIT is defined, it is used as the command to be executed when the v command is
invoked. The LESSEDIT string is expanded in the same way as the prompt strings. The de‐
fault value for LESSEDIT is:
%E ?lm+%lm. %g
Note that this expands to the editor name, followed by a + and the line number, followed
by the shell-escaped file name. If your editor does not accept the "+linenumber" syntax,
or has other differences in invocation syntax, the LESSEDIT variable can be changed to
modify this default.
SECURITY
When the environment variable LESSSECURE is set to 1, less runs in a "secure" mode. In
this mode, these features are disabled:
edit the edit command (v)
examine the examine command (:e)
glob metacharacters such as * in filenames,
and filename completion (TAB, ^L)
history history file
lesskey use of lesskey files (-k and --lesskey-src)
lessopen input preprocessor (LESSOPEN environment variable)
logfile log files (s and -o)
osc8 opening OSC 8 links (^O^O)
pipe the pipe command (|)
shell the shell and pshell commands (! and #)
stop stopping less via a SIGTSTP signal
tags use of tags files (-t)
The LESSSECURE_ALLOW environment variable can be set to a comma-separated list of names of
features which are selectively enabled when LESSSECURE is set. Each feature name is the
first word in each line in the above list. A feature name may be abbreviated as long as
the abbreviation is unambiguous. For example, if LESSSECURE=1 and
LESSSECURE_ALLOW=hist,edit were set, all of the above features would be disabled except
for history files and the edit command.
Less can also be compiled to be permanently in "secure" mode. In that case, the LESSSE‐
CURE and LESSSECURE_ALLOW variables are ignored.
COMPATIBILITY WITH MORE
If the environment variable LESS_IS_MORE is set to 1, or if the program is invoked via a
file link named "more" and the environment variable LESS_IS_MORE is not set to 0, less be‐
haves (mostly) in conformance with the POSIX more(1) command specification. In this mode,
less behaves differently in these ways:
The -e option works differently. If the -e option is not set, less behaves as if the -e
option were set. If the -e option is set, less behaves as if the -E option were set.
The -m option works differently. If the -m option is not set, the medium prompt is used,
and it is prefixed with the string "--More--". If the -m option is set, the short prompt
is used.
The -n option acts like the -z option. The normal behavior of the -n option is unavail‐
able in this mode.
The parameter to the -p option is taken to be a less command rather than a search pattern.
The LESS environment variable is ignored, and the MORE environment variable is used in its
place.
ENVIRONMENT VARIABLES
Environment variables may be specified either in the system environment as usual, or in a
lesskey(1) file. If environment variables are defined in more than one place, variables
defined in a local lesskey file take precedence over variables defined in the system envi‐
ronment, which take precedence over variables defined in the system-wide lesskey file.
COLUMNS
Sets the number of columns on the screen. Takes precedence over the number of
columns specified by the TERM variable. (But if you have a windowing system which
supports TIOCGWINSZ or WIOCGETD, the window system's idea of the screen size takes
precedence over the LINES and COLUMNS environment variables.)
EDITOR The name of the editor (used for the v command).
HOME Name of the user's home directory (used to find a lesskey file on Unix and OS/2
systems).
HOMEDRIVE, HOMEPATH
Concatenation of the HOMEDRIVE and HOMEPATH environment variables is the name of
the user's home directory if the HOME variable is not set (only in the Windows ver‐
sion).
INIT Name of the user's init directory (used to find a lesskey file on OS/2 systems).
LANG Language for determining the character set.
LC_CTYPE
Language for determining the character set.
LESS Options which are passed to less automatically.
LESSANSIENDCHARS
Characters which may end an ANSI color escape sequence (default "m").
LESSANSIMIDCHARS
Characters which may appear between the ESC character and the end character in an
ANSI color escape sequence (default "0123456789:;[?!"'#%()*+ ").
LESSANSIOSCALLOW
A comma-separated list of OSC types which are output directly to the terminal when
-R is in effect (default "8"; that is, only OSC 8 sequences are output directly).
LESSANSIOSCCHARS
Characters which may follow an ESC character to mark the start of an "OS Command"
sequence. All characters that follow this character up to a String Terminator
(ESC-backslash or BEL) are considered to be part of the OSC sequence (default "]").
If a character in LESSANSIOSCCHARS is followed by an asterisk, sequences that begin
with that character in the file contents are passed through to the terminal; other‐
wise only sequences that appear in a prompt string are passed through.
LESSBINFMT
Format for displaying non-printable, non-control characters.
LESSCHARDEF
Defines a character set.
LESSCHARSET
Selects a predefined character set.
LESSCLOSE
Command line to invoke the (optional) input-postprocessor.
LESSECHO
Name of the lessecho program (default "lessecho"). The lessecho program is needed
to expand metacharacters, such as * and ?, in filenames on Unix systems.
LESSEDIT
Editor prototype string (used for the v command). See discussion under PROMPTS.
LESSGLOBALTAGS
Name of the command used by the -t option to find global tags. Normally should be
set to "global" if your system has the global(1) command. If not set, global tags
are not used.
LESSHISTFILE
Name of the history file used to remember search commands and shell commands be‐
tween invocations of less. If set to "-" or "/dev/null", a history file is not
used. The default depends on the operating system, but is usually:
Linux and Unix
"$XDG_STATE_HOME/lesshst" or "$HOME/.local/state/lesshst" or "$XDG_DA‐
TA_HOME/lesshst" or "$HOME/.lesshst".
Windows and MS-DOS
"$HOME/_lesshst".
OS/2 "$HOME/lesshst.ini" or "$INIT/lesshst.ini".
LESSHISTSIZE
The maximum number of commands to save in the history file. The default is 100.
LESSKEYIN
Name of the default lesskey source file.
LESSKEY
Name of the default lesskey binary file. (Not used if "$LESSKEYIN" exists.)
LESSKEY_CONTENT
The value is parsed as if it were the parameter of a --lesskey-content option.
LESSKEYIN_SYSTEM
Name of the default system-wide lesskey source file.
LESSKEY_SYSTEM
Name of the default system-wide lesskey binary file. (Not used if "$LESSKEYIN_SYS‐
TEM" exists.)
LESSMETACHARS
List of characters which are considered "metacharacters" by the shell.
LESSMETAESCAPE
Prefix which less will add before each metacharacter in a command sent to the shell
(default "\").
LESSOPEN
Command line to invoke the (optional) input-preprocessor.
LESSSECURE
Runs less in "secure" mode. See discussion under SECURITY.
LESSSECURE_ALLOW
Enables individual features which are normally disabled by LESSSECURE. See discus‐
sion under SECURITY.
LESSSEPARATOR
String to be appended to a directory name in filename completion (default "\" on
MS-DOS, Windows, and OS/2; otherwise "/").
LESSUTFBINFMT
Format for displaying non-printable Unicode code points.
LESSUTFCHARDEF
Overrides the type of specified Unicode characters.
LESS_COLUMNS
Sets the number of columns on the screen. Unlike COLUMNS, takes precedence over
the system's idea of the screen size, so it can be used to make less use less than
the full screen width. If set to a negative number, sets the number of columns
used to this much less than the actual screen width.
LESS_LINES
Sets the number of lines on the screen. Unlike LINES, takes precedence over the
system's idea of the screen size, so it can be used to make less use less than the
full screen height. If set to a negative number, sets the number of lines used to
this much less than the actual screen height. When set, less repaints the entire
screen on every movement command, so scrolling may be slower.
LESS_DATA_DELAY
Duration (in milliseconds) after starting to read data from the input, after which
the "Waiting for data" message will be displayed. The default is 4000 (4 seconds).
LESS_IS_MORE
Emulate the more(1) command.
LESS_OSC8_xxx
Where "xxx" is a URI scheme such as "http" or "file", sets an OSC 8 handler for
opening OSC 8 links containing a URI with that scheme.
LESS_OSC8_ANY
Sets an OSC 8 handler for opening OSC 8 links for which there is no specific
LESS_OSC8_xxx handler set for the "xxx" scheme.
LESS_SHELL_LINES
When the -F option is set, less exits automatically if the number of screen lines
used to display the file is less than or equal to the screen height minus the value
of the LESS_SHELL_LINES variable. Thus, if you use a shell prompt which occupies
more than one screen line, this variable can be set to the number of lines used by
your prompt, to ensure that the entire file can be seen when -F is used. If not
set, LESS_SHELL_LINES is assumed to be 1.
LESS_SIGUSR1
If set to a string of one or more less command characters, those commands will be
executed when less receives a SIGUSR1 signal.
LESS_TERMCAP_xx
Where "xx" is any two characters, overrides the definition of the termcap "xx" ca‐
pability for the terminal.
LESS_TERMCAP_BRACKETED_PASTE_START
Overrides the standard ANSI escape sequence to enable bracketed paste. This is
used when the --no-paste option is in effect.
LESS_TERMCAP_BRACKETED_PASTE_END
Overrides the standard ANSI escape sequence to disable bracketed paste.
LESS_TERMCAP_MOUSE_START
Overrides the standard ANSI escape sequence to enable mouse reporting. This is
used when the --mouse option is in effect.
LESS_TERMCAP_MOUSE_END
Overrides the standard ANSI escape sequence to disable mouse reporting.
LESS_TERMCAP_SUSPEND
Defines an escape sequence to temporarily suspend screen updates. This is sent to
the terminal before clearing the screen. This can be used to avoid screen tearing
when the screen is redrawn on certain terminals.
LESS_TERMCAP_RESUME
Defines an escape sequence to resume screen updates. This is sent to the terminal
after displaying the prompt.
LESS_UNSUPPORT
A space-separated list of command line options. These options will be ignored
(with no error message) if they appear on the command line or in the LESS environ‐
ment variable. Options listed in LESS_UNSUPPORT can still be changed by the - and
-- commands. Each option in LESS_UNSUPPORT is a dash followed by a single charac‐
ter option letter, or two dashes followed by a long option name.
LINES Sets the number of lines on the screen. Takes precedence over the number of lines
specified by the TERM variable. (But if you have a windowing system which supports
TIOCGWINSZ or WIOCGETD, the window system's idea of the screen size takes prece‐
dence over the LINES and COLUMNS environment variables.)
MORE Options which are passed to less automatically when running in more-compatible
mode.
PATH User's search path (used to find a lesskey file on MS-DOS, Windows, and OS/2 sys‐
tems).
POSIXLY_CORRECT
If set to any value, all option arguments on the command line are expected to ap‐
pear before any filename arguments. This must be set as an actual environment
variable, not in a lesskey file.
SHELL The shell used to execute the ! command, as well as to expand filenames.
TERM The type of terminal on which less is being run.
VISUAL The name of the editor (used for the v command).
XDG_CONFIG_HOME
Possible location of the lesskey file; see the KEY BINDINGS section.
XDG_DATA_HOME
Possible location of the history file; see the description of the LESSHISTFILE en‐
vironment variable.
XDG_STATE_HOME
Possible location of the history file; see the description of the LESSHISTFILE en‐
vironment variable.
SEE ALSO
lesskey(1), lessecho(1)
COPYRIGHT
Copyright (C) 1984-2025 Mark Nudelman
less is part of the GNU project and is free software. You can redistribute it and/or mod‐
ify it under the terms of either (1) the GNU General Public License as published by the
Free Software Foundation; or (2) the Less License. See the file README in the less dis‐
tribution for more details regarding redistribution. You should have received a copy of
the GNU General Public License along with the source for less; see the file COPYING. If
not, write to the Free Software Foundation, 59 Temple Place, Suite 330, Boston, MA
02111-1307, USA. You should also have received a copy of the Less License; see the file
LICENSE.
less is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
AUTHOR
Mark Nudelman
Report bugs at https://github.com/gwsw/less/issues.
For more information, see the less homepage at
https://greenwoodsoftware.com/less.
Version 685: 04 Oct 2025 LESS(1)
Source notice
This page is derived from the original manual page distributed with the package. For packaging decisions, maintainers should also consult the upstream documentation and the RPM spec file.