less(1)
LESS(1) USER COMMANDS LESS(1)
NAME
less - opposite of more
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 which allows
backward movement in the file as well as forward movement.
Also, less does not have to read the entire input file
before starting, so with large input files it starts up fas-
ter 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 ter-
minals. (On a hardcopy terminal, lines which should be
printed at the top of the screen are prefixed with a caret.)
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.
COMMANDS
In the following descriptions, ^X means control-X. ESC
stands for the ESCAPE key; for example ESC-v means the two
character sequence "ESCAPE", then "v".
h or H
Help: display a summary of these commands. If you for-
get 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.
ESC-SPACE
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Like SPACE, but scrolls a full screenful, even if it
reaches end-of-file in the process.
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-) 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 option (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.
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ESC-} or ^RIGHTARROW
Scroll horizontally right to show the end of the long-
est 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.
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 behavior is similar to the "tail
-f" command.)
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 { command 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
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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
top 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, respec-
tively. For example, "ESC ^F < >" could be used to go
forward 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, respec-
tively. For example, "ESC ^B < >" could be used to go
backward 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 displayed line.
' (Single quote.) Followed by any lowercase or uppercase
letter, returns to the position which was previously
marked with that letter. Followed by another single
quote, returns to the position at which the last
"large" movement command was executed. Followed by a ^
or $, jumps to the beginning or end of the file respec-
tively. Marks are preserved when a new file is
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examined, so the ' command can be used to switch
between input files.
^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 regu-
lar expression, as recognized by the regular expression
library supplied by your system. The search starts at
the first line displayed (but see the -a and -j
options, which change this).
Certain characters are special if entered at the begin-
ning 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 current file without find-
ing 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 textual comparison.
?pattern
Search backward in the file for the N-th line contain-
ing 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 !
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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 pre-
vious 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.
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. 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 previous 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
command, 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
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case search commands do not turn highlighting back on.)
&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 ENTER),
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 rem-
inder that some lines in the file may be hidden.
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 textual 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.
Similarly, 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.
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: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.
= 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 option is changed but no mes-
sage 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 describ-
ing 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. You
must press ENTER or RETURN after typing the option
name. 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" com-
mand 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 letter.
-! 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
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setting. This does not work for numeric or string-
valued options.
--! Like the -! command, but takes a long option name
rather than a single option letter.
_ (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 example, +G causes less to ini-
tially 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 four commands may or may not be valid, depend-
ing on your particular installation.
v Invokes an editor to edit the current file being
viewed. The editor is taken from the environment vari-
able VISUAL if defined, or EDITOR if VISUAL is not
defined, or defaults to "vi" if neither VISUAL nor EDI-
TOR 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 per-
cent 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 simply
invokes a shell. On Unix systems, the shell is taken
from the environment variable SHELL, or defaults to
"sh". On MS-DOS and OS/2 systems, the shell is the
normal command processor.
| <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
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screen is included, regardless 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.
s filename
Save the input to a file. This only works if the input
is a pipe, not an ordinary file.
OPTIONS
Command line options are described below. Most options may
be changed while less is running, via the "-" command.
Most 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,
--quit-at-eof may be abbreviated --quit, but not --qui,
since both --quit-at-eof and --quiet begin with --qui. 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, you don't need the quotes, but you should replace
any percent signs in the options string by double percent
signs.
The environment variable is parsed before the command line,
so command line options override the LESS environment vari-
able. 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 ($) is found. For example, you can
set two -D options on MS-DOS like this:
LESS="Dn9.1$Ds4.1"
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If the --use-backslash option appears earlier in the
options, then a dollar sign or backslash 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 respectively; 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 kilobytes (1024 bytes). By
default 64 K 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 dis-
ables this automatic allocation of buffers for pipes,
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so that only 64 K (or the amount of space specified by
the -b option) is used for the pipe. Warning: use of
-B can result in erroneous display, since only the most
recently viewed part of the piped data is kept in
memory; any earlier data is lost.
-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 oth-
erwise change the behavior of less on a dumb terminal.
-Dxcolor or --color=xcolor
[MS-DOS only] Sets the color of the text displayed. x
is a single character which selects the type of text
whose color is being set: n=normal, s=standout, d=bold,
u=underlined, k=blink. color is a pair of numbers
separated by a period. The first number selects the
foreground color and the second selects the background
color of the text. A single number N is the same as
N.M, where M is the normal background color. The color
may start or end with u to use underline (with the nor-
mal color, if by itself), if the system supports it
(Windows only). x may also be a to toggle strict ANSI
sequence rendering (SGR mode).
-e or --quit-at-eof
Causes less to automatically exit the second time it
reaches end-of-file. By default, 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 device 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
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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.
-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 implied.)
-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 upper-
case 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 rela-
tive 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 win-
dow is resized, so that the target line remains at the
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specified fraction of the screen height. 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 searches 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 respectively.
-J or --status-column
Displays a status column at the left edge of the
screen. The status column shows the lines that matched
the current search, and any lines that are marked (via
the m or M command). The status column is also used if
the -w or -W option is in effect.
-kfilename or --lesskey-file=filename
Causes less to open and interpret the named file as a
lesskey (1) file. Multiple -k options may be speci-
fied. If the LESSKEY or LESSKEY_SYSTEM environment
variable is set, or if a lesskey file is found in a
standard place (see KEY BINDINGS), it is also used as a
lesskey file.
-K or --quit-on-intr
Causes less to exit immediately (with status 2) when an
interrupt character (usually ^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 below). 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), 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.
-n or --line-numbers
Suppresses line numbers. The default (to use line
numbers) may cause less to run more slowly in some
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cases, especially with a very large input file.
Suppressing line numbers with the -n option will avoid
this problem. 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 also 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 applies only when the input file
is a pipe, not an ordinary file. If the file already
exists, less will ask for confirmation before overwrit-
ing 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 option 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
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LESS(1) USER COMMANDS LESS(1)
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.
-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
displayed as "^A". 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 character). Thus,
various display problems may result, such as long lines
being split in the wrong place.
-R or --RAW-CONTROL-CHARS
Like -r, but only ANSI "color" escape sequences are
output in "raw" form. Unlike -r, the screen appearance
is maintained correctly in most cases. ANSI "color"
escape sequences are sequences of the form:
ESC [ ... m
where the "..." is zero or more color specification
characters For the purpose of keeping track of screen
appearance, ANSI color escape sequences are assumed to
not move the cursor. You can make less think that
characters other than "m" can end ANSI color escape
sequences by setting the environment variable LESSAN-
SIENDCHARS to the list of characters 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.
-s or --squeeze-blank-lines
Causes consecutive blank lines to be squeezed into a
single blank line. This is useful when viewing nroff
output.
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-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 shown. The default is to wrap long lines; that is,
display the remainder on the next line.
-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 com-
mand. 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 specified 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 "format-
ting characters" (as defined by Unicode) to be treated
as control characters; that is, they are handled as
specified 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 between two identical
characters are treated specially: the overstruck text
is printed using the terminal's hardware boldface capa-
bility. Other backspaces are deleted, along with the
preceding character. Carriage returns immediately fol-
lowed by a newline are deleted. Other carriage returns
are handled as specified by the -r option. Text which
is overstruck or underlined can be searched for if nei-
ther -u nor -U is in effect.
-V or --version
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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 tar-
get line after a g or p command. The highlight is
removed at the next command which causes movement. The
entire 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 spac-
ing 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 deini-
tialization strings to the terminal. This is sometimes
desirable if the deinitialization string does something
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 screenful. 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.
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.
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-cc or --quotes=cc
Changes the filename quoting character. This may be
necessary if you are trying to name a file which con-
tains both spaces and quote characters. Followed by a
single character, this changes the quote character to
that character. Filenames containing 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 character. 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
number 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, so that the actual scroll remains at the
specified fraction of the screen width.
--follow-name
Normally, if the input file is renamed while an F com-
mand 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.
--no-keypad
Disables sending the keypad initialization and deini-
tialization strings to the terminal. This is sometimes
useful if the keypad strings make the numeric keypad
behave in an undesirable manner.
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--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.
--rscroll
This option changes the character used to mark trun-
cated lines. It may begin with a two-character attri-
bute indicator like LESSBINFMT does. If there is no
attribute indicator, standout is used. If set to "-",
truncated lines are not marked.
-- A command line argument of "--" marks the end of option
arguments. Any arguments following this are inter-
preted as filenames. This can be useful when viewing a
file whose name begins with a "-" or "+".
+ 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.
LINE EDITING
When entering 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 in 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.
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^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 can-
cel the command if the command 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 DOWNARROW, it will retrieve
the next command which begins with that text.
TAB Complete the partial filename to the left of the cur-
sor. 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 systems, a "\" is appended.)
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.
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LESS(1) USER COMMANDS LESS(1)
^L Complete the partial filename to the left of the cur-
sor. 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)
Delete the entire command line, or cancel the command
if the command line is empty. 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 using the program
lesskey (1) to create a lesskey file. This file specifies a
set of command keys and an action associated with each key.
You may also use lesskey to change the line-editing keys
(see LINE EDITING), and to set environment variables. If
the environment variable LESSKEY is set, less uses that as
the name of the lesskey file. Otherwise, less looks in a
standard place for the lesskey file: On Unix systems, less
looks for a lesskey file called "$HOME/.less". On MS-DOS
and Windows systems, less looks for a lesskey file called
"$HOME/_less", and if it is not found there, then looks for
a lesskey file called "_less" in any directory specified in
the PATH environment variable. On OS/2 systems, less looks
for a lesskey file called "$HOME/less.ini", and if it is not
found, then looks for a lesskey file called "less.ini" in
any directory specified in the INIT environment variable,
and if it not found there, then looks for a lesskey file
called "less.ini" in any directory specified in the PATH
environment variable. See the lesskey manual page for more
details. A system-wide lesskey 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 local file take precedence over those in the system-wide
file. If the environment variable LESSKEY_SYSTEM is set,
less uses that as the name of the system-wide lesskey file.
Otherwise, less looks in a standard place for the system-
wide lesskey file: On Unix systems, the system-wide lesskey
file is /etc/sysless. (However, if less was built with a
different sysconf directory than /etc, that directory is
where the sysless file is found.) On MS-DOS and Windows
systems, the system-wide lesskey file is c:\_sysless. On
OS/2 systems, the system-wide lesskey file is
c:\sysless.ini.
INPUT PREPROCESSOR
You may define an "input preprocessor" for less. Before
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LESS(1) USER COMMANDS LESS(1)
less opens a file, it first gives your 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 entered 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 prepro-
cessor 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 preprocessor.
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 input postprocessor, which may
perform any desired clean-up action (such as deleting the
replacement 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 compressed format, but still let
less view them directly:
lessopen.sh:
#! /bin/sh
case "$1" in
*.Z) uncompress -c $1 >/tmp/less.$$ 2>/dev/null
if [ -s /tmp/less.$$ ]; then
echo /tmp/less.$$
else
rm -f /tmp/less.$$
fi
;;
esac
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LESS(1) USER COMMANDS LESS(1)
lessclose.sh:
#! /bin/sh
rm $2
To use these scripts, put them both where they can be exe-
cuted 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 decompress
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 replacement
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 char-
acter in the LESSOPEN environment variable a vertical bar
(|) to signify that the input preprocessor is an input pipe.
As with non-pipe input 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
becomes meaningful. If the exit status is zero, the output
is considered to be replacement text, even if it is empty.
If the exit status is nonzero, any output is ignored and the
original file is used. For compatibility with previous ver-
sions of less, if LESSOPEN starts with only one vertical
bar, the exit status of the preprocessor is ignored.
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LESS(1) USER COMMANDS LESS(1)
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 con-
sidered 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 three 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.
A "character set" is simply a description of which charac-
ters are to be considered normal, control, and binary. The
LESSCHARSET environment variable may be used to select a
character 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.
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LESS(1) USER COMMANDS LESS(1)
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 Win-
dows (cp 1251).
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
control, 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 example, and does not necessarily represent any real
character set.)
This table shows the value of LESSCHARDEF which is
equivalent to each of the possible values 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
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LESS(1) USER COMMANDS LESS(1)
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 latin1.
Control and binary characters are displayed in standout
(reverse video). Each such character is displayed in caret
notation if possible (e.g. ^A for control-A). Caret nota-
tion is used only if inverting the 0100 bit results in a
normal printable character. Otherwise, the character is
displayed as a hex number in angle brackets. This format
can be changed by setting the LESSBINFMT environment vari-
able. 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 nor-
mal. If LESSBINFMT does not begin with a "*", normal attri-
bute is assumed. The remainder of LESSBINFMT is a string
which may include one printf-style escape sequence (a % fol-
lowed by x, X, o, d, etc.). For example, if LESSBINFMT is
"*u[%x]", binary characters are displayed in underlined hex-
adecimal surrounded by brackets. The default if no LESS-
BINFMT 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 environ-
ment 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
sequence, octets of a complete but non-shortest form
sequence, illegal octets, and stray trailing octets) are
displayed individually using LESSBINFMT so as to facilitate
diagnostic of how the UTF-8 file is ill-formed.
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LESS(1) USER COMMANDS LESS(1)
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 interpreted 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:
%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 display 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 speci-
fied 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 vari-
able 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.
%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.
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LESS(1) USER COMMANDS LESS(1)
%L Replaced by the line number of the last line in the
input file.
%m Replaced by the total number of input files.
%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 view-
ing files via a tags list using 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 question 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 condi-
tion 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.
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LESS(1) USER COMMANDS LESS(1)
?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
included 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 number, if known, otherwise
the percent if known, otherwise the byte offset if known.
Otherwise, 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
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LESS(1) USER COMMANDS LESS(1)
string "(END)" is printed followed by the name of the next
file, if there is one. Finally, 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 rea-
dability 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 pur-
pose: if an environment variable 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 default value for LESSEDIT is:
%E ?lm+%lm. %f
Note that this expands to the editor name, followed by a +
and the line number, followed by the file name. If your
editor does not accept the "+linenumber" syntax, or has
other differences in invocation syntax, the LESSEDIT vari-
able can be changed to modify this default.
SECURITY
When the environment variable LESSSECURE is set to 1, less
runs in a "secure" mode. This means these features are dis-
abled:
! the shell command
| the pipe command
:e the examine command.
v the editing command
s -o
log files
-k use of lesskey files
-t use of tags files
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LESS(1) USER COMMANDS LESS(1)
metacharacters in filenames, such as *
filename completion (TAB, ^L)
Less can also be compiled to be permanently in "secure"
mode.
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", less
behaves (mostly) in conformance with the POSIX "more" com-
mand 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 unavailable 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 environ-
ment variables are defined in more than one place, variables
defined in a local lesskey file take precedence over vari-
ables defined in the system environment, which take pre-
cedence over variables defined in the system-wide lesskey
file.
COLUMNS
Sets the number of columns on the screen. Takes pre-
cedence 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
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LESS(1) USER COMMANDS LESS(1)
The name of the editor (used for the v command).
HOME Name of the user's home directory (used to find a less-
key 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 less-
key 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:;[?!"'#%()*+ ".
LESSBINFMT
Format for displaying non-printable, non-control char-
acters.
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.
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LESS(1) USER COMMANDS LESS(1)
LESSGLOBALTAGS
Name of the command used by the -t option to find glo-
bal 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 com-
mands and shell commands between invocations of less.
If set to "-" or "/dev/null", a history file is not
used. The default is "$HOME/.lesshst" on Unix systems,
"$HOME/_lesshst" on DOS and Windows systems, or
"$HOME/lesshst.ini" or "$INIT/lesshst.ini" on OS/2 sys-
tems.
LESSHISTSIZE
The maximum number of commands to save in the history
file. The default is 100.
LESSKEY
Name of the default lesskey(1) file.
LESSKEY_SYSTEM
Name of the default system-wide lesskey(1) file.
LESSMETACHARS
List of characters which are considered "metacharac-
ters" by the shell.
LESSMETAESCAPE
Prefix which less will add before each metacharacter in
a command sent to the shell. If LESSMETAESCAPE is an
empty string, commands containing metacharacters will
not be passed to the shell.
LESSOPEN
Command line to invoke the (optional) input-
preprocessor.
LESSSECURE
Runs less in "secure" mode. See discussion under SECU-
RITY.
LESSSEPARATOR
String to be appended to a directory name in filename
completion.
LESSUTFBINFMT
Format for displaying non-printable Unicode code
points.
LESS_IS_MORE
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LESS(1) USER COMMANDS LESS(1)
Emulate the more (1) command.
LINES
Sets the number of lines on the screen. Takes pre-
cedence 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 precedence 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 and OS/2 systems).
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).
SEE ALSO
lesskey(1)
COPYRIGHT
Copyright (C) 1984-2017 Mark Nudelman
less is part of the GNU project and is free software. You
can redistribute it and/or modify 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 distribution 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.
Last change: Version 530: 05 Dec 2017 35
LESS(1) USER COMMANDS LESS(1)
AUTHOR
Mark Nudelman
Send bug reports or comments to <bug-less@gnu.org>
See http://www.greenwoodsoftware.com/less/bugs.html for the
latest list of known bugs in less.
For more information, see the less homepage at
http://www.greenwoodsoftware.com/less.
Last change: Version 530: 05 Dec 2017 36
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