| LESS(1) | General Commands Manual | LESS(1) |
less, more
— view files
less | more |
-? |
less | more |
--help |
less | more |
-V |
less | more |
--version |
less | more |
[-[+]AaBCcdEeFfGgIiJKLMmNnQqRrSsUuVWwX~]
[-b space]
[-h lines]
[-j line]
[-k keyfile]
[-O | -o logfile]
[-P prompt]
[-p pattern]
[-T tagsfile]
[-t tag]
[-x tab,...]
[-y lines]
[-[z] lines]
[-# shift]
[+[+] cmd]
[--]
[filename ...] |
less is a program similar to the
traditional 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 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 terminals. (On a hardcopy terminal, lines which should be printed
at the top of the screen are prefixed with a caret.)
This version of less also acts as
more(1) if it is called as
more. In this mode, the differences are in the
prompt and that more exits by default when it gets
to the end of the file. Commands are based on both traditional
more and
vi(1). 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 example ESC-v means the two character sequence "ESCAPE", then "v".
h |
HSPACE
| ^V |
f |
^FzESC-SPACEENTER
|
RETURN
| ^N |
e |
^E |
j |
^Jd |
^Db |
^B |
ESC-vwy |
^Y |
^P |
k |
^Ku |
^UESC-)
|
RIGHTARROWESC-(
|
LEFTARROWr |
^R |
^LRFg |
< |
ESC-<G |
> |
ESC->p |
%P{}()[]ESC-^FESC-^Bm'^X^X/patternCertain 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
|
!^E
|
*^F
|
@^K^R?patternCertain characters are special, as in the / command:
^N
|
!^E
|
*^F
|
@^K^RESC-/patternESC-?patternnNESC-nESC-NESC-u&patternCertain characters are special as in the / command:
:e
[filename]^X^V
| E:n:p:t:x:dtT= |
^G |
:f----+--+-!--!___+cmdless to initially display
each file starting at the end rather than the beginning.Vless being run.q |
Q |
:q |
:Q |
ZZless.The following four commands may or may not be valid, depending on your particular installation.
vVISUAL, 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-commandSHELL, or defaults to "sh".<m>
shell-commands
filenameCommand 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 if the command is less,
or from the environment variable MORE if the command
is more. For example, to avoid typing "less
-options ..." each time less is invoked, you
might tell csh(1):
setenv LESS -optionsor if you use sh(1):
LESS="-options"; export
LESSThe environment variable is parsed before the command line, so
command line options override 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 "-+".
For options like -P which take a following string, a dollar sign ($) must be used to signal the end of the string. For example, to separate a prompt value from any other options with dollar sign between them:
LESS="-Ps--More--$-C
-e"-? |
--helpless (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 |
--SEARCH-SKIP-SCREEN-a |
--search-skip-screen-B |
--auto-buffers-bn
|
--buffers=nless will use
for each file, in units of kilobytes (1024 bytes). By default 64K 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.-C |
--CLEAR-SCREENless.-c |
--clear-screen-d |
--dumb
(less only)less on a dumb
terminal. This option is on by default when invoked as
more.-d
(more only)-E |
--QUIT-AT-EOFless to automatically exit the first time
it reaches end-of-file.-e |
--quit-at-eofless to automatically exit the second time
it reaches end-of-file. By default, the only way to exit
less is via the "q" command.-F |
--quit-if-one-screenless to automatically exit if the entire
file can be displayed on the first screen.-f |
--forceless will
refuse to open non-regular files.-G |
--HILITE-SEARCH-g |
--hilite-searchless 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.-hn
|
--max-back-scroll=n-I |
--IGNORE-CASE-i |
--ignore-case-J |
--status-column-jn
|
--jump-target=n-K |
--quit-on-intrless 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.-kfilename
|
--lesskey-file=filenameless to open and interpret the named file
as a lesskey(1) file.
Multiple -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 BINDINGS), it is
also used as a lesskey file.-L |
--no-lessopenLESSOPEN 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. When invoked as more, the
LESSOPEN environment variable is ignored by
default.-M |
--LONG-PROMPTless to prompt even more verbosely than
more.-m |
--long-promptless to prompt verbosely (like more), with
the percent into the file. By default, less
prompts with a colon.-N |
--LINE-NUMBERS-n |
--line-numbersless to run more slowly in some 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).-Ofilename
|
--LOG-FILE=filenameIf 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.
-ofilename
|
--log-file=filenameless 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 overwriting it.-Pprompt
|
--prompt=promptLESS
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.-ppattern
|
--pattern=patternless to start at the first
occurrence of pattern in the file.-Q |
--QUIET
|
--SILENT-q |
--quiet
|
--silent-R |
--RAW-CONTROL-CHARSESC [ ... mwhere 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 LESSANSIENDCHARS 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.
-r |
--raw-control-charsless 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.-S |
--chop-long-lines-s |
--squeeze-blank-lines-Ttagsfile
|
--tag-file=tagsfile-ttag
|
--tag=tagLESSGLOBALTAGS is set, it is taken to be the name
of a command compatible with
global, 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.-U |
--UNDERLINE-SPECIALBy 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 capability. Other backspaces are deleted, along with the preceding character. Carriage returns immediately followed 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 neither -u nor -U is in effect.
-u |
--underline-special-V |
--versionless.-W |
--HILITE-UNREAD-w |
--hilite-unread-X |
--no-init-xn,...
|
--tabs=n,...-yn
|
--max-forw-scroll=n-[z]n
|
--window=nmore. 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.--follow-nameless 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--quotes=cc-~ |
--tilde-#
|
--shift--+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 previously may also be used to set (or change) an
initial command for every file.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. 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.
LESSSEPARATOR
can be used to specify a different character to append to a directory
name.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 for a lesskey file called
"$HOME/.less". See the
lesskey(1) 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 OpenBSD, the system-wide lesskey
file is /etc/sysless.
You may define an "input preprocessor" for
less. Before 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 preprocessor 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, 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
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 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 character in the LESSOPEN
environment variable a vertical bar (|) to signify that the input
preprocessor is an input pipe.
For example, this script will work like the previous example scripts:
lesspipe.sh:
#! /bin/sh case "$1" in *.Z) uncompress -c $1 2>/dev/null ;; esac
To use this script, put it where it can be executed and set LESSOPEN="|lesspipe.sh %s". 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 (|-), 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.
There are three types of characters in the input file:
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 character set. Possible values for
LESSCHARSET are:
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 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 notation 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 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
include 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 surrounded 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 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.
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:
VISUAL environment variable, or the
EDITOR environment variable if
VISUAL is not defined). See the discussion of the
LESSEDIT feature below.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 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:
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(file %i of %m) ..?e(END) ?x- Next\: %x..%tThis 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. 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 readability only.
?f%f .?m(file %i of %m) .?e(END) ?x- Next\: %x.: ?pB%pB\%:byte %bB?s/%s...%t ?f%f .?n?m(file %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(file %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 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. %fNote 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 variable can be changed to
modify this default.
When the environment variable LESSSECURE
is set to 1, less runs in a "secure" mode.
This means these features are disabled:
Less can also be compiled to be permanently in "secure" mode.
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" 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 and -F
options were set.
The -m option works differently. If the -m option is not set, the medium prompt is used. 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 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 environment, which take precedence over variables defined in the system-wide lesskey file.
COLUMNSEDITORHOMELANGLC_CTYPELESSless
automatically.LESSANSIENDCHARSLESSANSIMIDCHARSLESSBINFMTLESSCHARDEFLESSCHARSETLESSCLOSELESSEDITLESSGLOBALTAGSLESSHISTFILEless. If set to
"-" or "/dev/null", a history file is not used. The
default is "-".LESSHISTSIZELESSKEYLESSKEY_SYSTEMLESSMETACHARSLESSMETAESCAPEless 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.LESSOPENLESSSECURELESSSEPARATORLESSUTFBINFMTLESS_IS_MORELINESSHELLTERMless is being
run.VISUALThe more utility is compliant with the
IEEE Std 1003.1-2008 (“POSIX.1”)
specification, though its presence is optional.
The flags
[-aBbCdEFfGghIJjkLMmNOoPQqRrSTUVWwXxyz~#] are
extensions to that specification.
Mark Nudelman <markn@greenwoodsoftware.com>
Send bug reports or comments to the above address or to <bug-less@gnu.org>.
For more information, see the less homepage at http://www.greenwoodsoftware.com/less.
| July 16, 2013 | OpenBSD-5.5 |