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less.nro.VER
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less.nro.VER
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'\" t
.TH LESS 1 "Version @@VERSION@@: @@DATE@@"
.SH NAME
less \- opposite of more
.SH SYNOPSIS
.B "less \-?"
.br
.B "less \-\-help"
.br
.B "less \-V"
.br
.B "less \-\-version"
.br
.B "less [\-[+]aABcCdeEfFgGiIJKLmMnNqQrRsSuUVwWX~]"
.br
.B " [\-b \fIspace\/\fP] [\-h \fIlines\/\fP] [\-j \fIline\/\fP] [\-k \fIkeyfile\/\fP]"
.br
.B " [\-{oO} \fIlogfile\/\fP] [\-p \fIpattern\/\fP] [\-P \fIprompt\/\fP] [\-t \fItag\/\fP]"
.br
.B " [\-T \fItagsfile\/\fP] [\-x \fItab\/\fP,...] [\-y \fIlines\/\fP] [\-[z] \fIlines\/\fP]"
.br
.B " [\-# \fIshift\/\fP] [+[+]\fIcmd\/\fP] [\-\-] [\fIfilename\/\fP]..."
.br
(See the OPTIONS section for alternate option syntax with long option names.)
.
.SH DESCRIPTION
.I Less
is a program similar to
.IR more (1),
but which allows backward movement
in the file as well as forward movement.
Also,
.I 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
.IR vi (1).
.I 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.)
.PP
Commands are based on both
.I more
and
.IR vi .
Commands may be preceded by a decimal number,
called N in the descriptions below.
The number is used by some commands, as indicated.
.
.SH 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".
.IP "h or H"
Help: display a summary of these commands.
If you forget all the other commands, remember this one.
.IP "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.
.IP "z"
Like SPACE, but if N is specified, it becomes the new window size.
.IP "ESC-SPACE"
Like SPACE, but scrolls a full screenful, even if it reaches
end-of-file in the process.
.IP "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.
.IP "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.
.IP "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.
.IP "w"
Like ESC-v, but if N is specified, it becomes the new window size.
.IP "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.
.IP "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.
.IP "J"
Like j, but continues to scroll beyond the end of the file.
.IP "K or Y"
Like k, but continues to scroll beyond the beginning of the file.
.IP "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.
.IP "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.
.IP "ESC-} or ^RIGHTARROW"
Scroll horizontally right to show the end of the longest displayed line.
.IP "ESC-{ or ^LEFTARROW"
Scroll horizontally left back to the first column.
.IP "r or ^R or ^L"
Repaint the screen.
.IP R
Repaint the screen, discarding any buffered input.
That is, reload the current file.
Useful if the file is changing while it is being viewed.
.IP "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.)
To stop waiting for more data, enter the interrupt character (usually ^C).
On some systems you can also use ^X.
.IP "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.
.IP "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.)
.IP "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.)
.IP "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.
.IP "p or %"
Go to a position N percent into the file.
N should be between 0 and 100, and may contain a decimal point.
.IP "P"
Go to the line containing byte offset N in the file.
.IP "{"
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 line,
a number N may be used to specify the N-th bracket on the line.
.IP "}"
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.
.IP "("
Like {, but applies to parentheses rather than curly brackets.
.IP ")"
Like }, but applies to parentheses rather than curly brackets.
.IP "["
Like {, but applies to square brackets rather than curly brackets.
.IP "]"
Like }, but applies to square brackets rather than curly brackets.
.IP "ESC-^F"
Followed by two characters,
acts like {, but uses the two characters as open and close brackets,
respectively.
For example, "ESC ^F < >" could be used to
go forward to the > which matches the < in the top displayed line.
.IP "ESC-^B"
Followed by two characters,
acts like }, but uses the two characters as open and close brackets,
respectively.
For example, "ESC ^B < >" could be used to
go backward to the < which matches the > in the bottom displayed line.
.IP 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.
.IP M
Acts like m, except the last displayed line is marked
rather than the first displayed line.
.IP "'"
(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 respectively.
Marks are preserved when a new file is examined,
so the ' command can be used to switch between input files.
.IP "^X^X"
Same as single quote.
.IP "ESC-m"
Followed by any lowercase or uppercase letter,
clears the mark identified by that letter.
.IP /pattern
Search forward in the file for the N-th line containing the pattern.
N defaults to 1.
The pattern is a regular expression, as recognized by
the regular expression library supplied by your system.
The search starts at the first line displayed
(but see the \-a and \-j options, which change this).
.sp
Certain characters are special
if entered at the beginning of the pattern;
they modify the type of search rather than become part of the pattern:
.RS
.IP "^N or !"
Search for lines which do NOT match the pattern.
.IP "^E or *"
Search multiple files.
That is, if the search reaches the END of the current file
without finding a match,
the search continues in the next file in the command line list.
.IP "^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 settings of the \-a or \-j options.
.IP "^K"
Highlight any text which matches the pattern on the current screen,
but don't move to the first match (KEEP current position).
.IP "^R"
Don't interpret regular expression metacharacters;
that is, do a simple textual comparison.
.IP "^W"
WRAP around the current file.
That is, if the search reaches the end of the current file
without finding a match, the search continues from the first line of the
current file up to the line where it started.
If the ^W modifier is set, the ^E modifier is ignored.
.RE
.IP ?pattern
Search backward in the file for the N-th line containing the pattern.
The search starts at the last line displayed
(but see the \-a and \-j options, which change this).
.sp
Certain characters are special as in the / command:
.RS
.IP "^N or !"
Search for lines which do NOT match the pattern.
.IP "^E or *"
Search multiple files.
That is, if the search reaches the beginning of the current file
without finding a match,
the search continues in the previous file in the command line list.
.IP "^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.
.IP "^K"
As in forward searches.
.IP "^R"
As in forward searches.
.IP "^W"
WRAP around the current file.
That is, if the search reaches the beginning of the current file
without finding a match, the search continues from the last line of the
current file up to the line where it started.
.RE
.IP "ESC-/pattern"
Same as "/*".
.IP "ESC-?pattern"
Same as "?*".
.IP 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.
.IP N
Repeat previous search, but in the reverse direction.
.IP "ESC-n"
Repeat previous search, but crossing file boundaries.
The effect is as if the previous search were modified by *.
.IP "ESC-N"
Repeat previous search, but in the reverse direction
and crossing file boundaries.
.IP "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 case search commands do not turn highlighting back on.)
.IP "ESC-U"
Like ESC-u but also clears the saved search pattern.
If the status column is enabled via the \-J option,
this clears all search matches marked in the status column.
.IP "&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 reminder that some lines in the file may be hidden.
Multiple & commands may be entered, in which case only lines
which match all of the patterns will be displayed.
.sp
Certain characters are special as in the / command:
.RS
.IP "^N or !"
Display only lines which do NOT match the pattern.
.IP "^R"
Don't interpret regular expression metacharacters;
that is, do a simple textual comparison.
.RE
.IP ":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).
.IP "^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.
.IP ":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.
.IP ":p"
Examine the previous file in the command line list.
If a number N is specified, the N-th previous file is examined.
.IP ":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.
.IP ":d"
Remove the current file from the list of files.
.IP "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.
.IP "T"
Go to the previous tag, if there were more than one matches for the current tag.
.IP "= 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.
.IP \-
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 message is printed.
If the option letter has a numeric value (such as \-b or \-h),
or a string value (such as \-P or \-t),
a new value may be entered after the option letter.
If no new value is entered, a message describing
the current setting is printed and nothing is changed.
.IP \-\-
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.
.IP \-+
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 "\-+\fIX\fP" command does the same thing
as "\-+\fIX\fP" on the command line.)
This does not work for string-valued options.
.IP \-\-+
Like the \-+ command, but takes a long option name
rather than a single option letter.
.IP \-!
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 setting.
This does not work for numeric or string-valued options.
.IP \-\-!
Like the \-!\& command, but takes a long option name
rather than a single option letter.
.IP _
(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.
.IP __
(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.
.IP +cmd
Causes the specified cmd to be executed each time a new file is examined.
For example, +G causes
.I less
to initially display each file starting at the end
rather than the beginning.
.IP V
Prints the version number of
.I less
being run.
.IP "q or Q or :q or :Q or ZZ"
Exits
.IR less .
.PP
The following
four
commands may or may not be valid, depending on your particular installation.
.
.IP v
Invokes an editor to edit the current file being viewed.
The editor is taken from the environment variable VISUAL if defined,
or EDITOR if VISUAL is not defined,
or defaults to "vi" if neither VISUAL nor EDITOR is defined.
See also the discussion of LESSEDIT under the section on PROMPTS below.
.IP "! shell-command"
Invokes a shell to run the shell-command given.
A percent sign (%) in the command is replaced by the name of the
current file.
A pound sign (#) is replaced by the name of the previously examined file.
"!!" repeats the last shell command.
"!" with no shell command 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.
.IP "| <m> shell-command"
<m> represents any mark letter.
Pipes a section of the input file to the given shell command.
The section of the file to be piped is between the position marked by
the letter and the current screen.
The entire current screen is included, 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.
.IP "s filename"
Save the input to a file.
This only works if the input is a pipe, not an ordinary file.
.
.SH OPTIONS
Command line options are described below.
Most options may be changed while
.I less
is running, via the "\-" command.
.PP
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.
.PP
Options are also taken from the environment variable "LESS".
For example,
to avoid typing "less \-options \&...\&" each time
.I less
is invoked, you might tell
.IR csh :
.sp
setenv LESS "\-options"
.sp
or if you use
.IR sh :
.sp
LESS="\-options"; export LESS
.sp
On MS-DOS, you don't need the quotes, but you should replace any
percent signs in the options string by double percent signs.
.sp
The 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 "\-+".
.sp
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 ($) is found.
For example, you can set two \-D options on MS-DOS like this:
.sp
LESS="Dn9.1$Ds4.1"
.sp
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.
.IP "\-? or \-\-help"
This option displays a summary of the commands accepted by
.I 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: "\-\e?".)
.IP "\-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.
.IP "\-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.
.IP "\-b\fIn\fP or \-\-buffers=\fIn\fP"
Specifies the amount of buffer space
.I less
will use for each file, in units of kilobytes (1024 bytes).
By default 64\ KB of buffer space is used for each file
(unless the file is a pipe; see the \-B option).
The \-b option specifies instead that \fIn\fP kilobytes of
buffer space should be used for each file.
If \fIn\fP is \-1, buffer space is unlimited; that is,
the entire file can be read into memory.
.IP "\-B or \-\-auto-buffers"
By default, when data is read from a pipe,
buffers are allocated automatically as needed.
If a large amount of data is read from the pipe, this can cause
a large amount of memory to be allocated.
The \-B option disables this automatic allocation of buffers for pipes,
so that only 64\ KB
(or the amount of space specified by the \-b option)
is used for the pipe.
Warning: use of \-B can result in erroneous display, since only the
most recently viewed part of the piped data is kept in memory;
any earlier data is lost.
.IP "\-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.
.IP "\-C or \-\-CLEAR-SCREEN"
Same as \-c, for compatibility with older versions of
.IR less .
.IP "\-d or \-\-dumb"
The \-d option suppresses the error message
normally displayed if the terminal is dumb;
that is, lacks some important capability,
such as the ability to clear the screen or scroll backward.
The \-d option does not otherwise change the behavior of
.I less
on a dumb terminal.
.IP "\-D\fBx\fP\fIcolor\fP or \-\-color=\fBx\fP\fIcolor\fP"
Changes the color of different parts of the displayed text.
\fBx\fP is a single character which selects the type of text
whose color is being set:
.RS
.IP "B"
Binary characters.
.IP "C"
Control characters.
.IP "E"
Errors and informational messages.
.IP "H"
Header lines and columns, set via the \-\-header option.
.IP "M"
Mark letters in the status column.
.IP "N"
Line numbers enabled via the \-N option.
.IP "P"
Prompts.
.IP "R"
The rscroll character.
.IP "S"
Search results.
.IP "W"
The highlight enabled via the \-w option.
.IP "d"
Bold text.
.IP "k"
Blinking text.
.IP "s"
Standout text.
.IP "u"
Underlined text.
.RE
.RS
The uppercase letters can be used only when the \-\-use-color option is enabled.
When text color is specified by both an uppercase letter and a lowercase letter,
the uppercase letter takes precedence.
For example, error messages are normally displayed as standout text.
So if both "s" and "E" are given a color, the "E" color applies
to error messages, and the "s" color applies to other standout text.
The "d" and "u" letters refer to bold and underline text formed by
overstriking with backspaces (see the \-u option),
not to text using ANSI escape sequences with the \-R option.
.PP
A lowercase letter may be followed by a + to indicate that
both the normal format change and the specified color should both be used.
For example, \-Dug displays underlined text as green without underlining;
the green color has replaced the usual underline formatting.
But \-Du+g displays underlined text as both green and in underlined format.
.PP
\fIcolor\fP is either a 4-bit color string or an 8-bit color string:
.PP
A 4-bit color string is zero, one or two characters, where
the first character specifies the foreground color and
the second specifies the background color as follows:
.IP "b"
Blue
.IP "c"
Cyan
.IP "g"
Green
.IP "k"
Black
.IP "m"
Magenta
.IP "r"
Red
.IP "w"
White
.IP "y"
Yellow
.PP
The corresponding upper-case letter denotes a brighter shade of the color.
For example, \-DNGk displays line numbers as bright green text on a black
background, and \-DEbR displays error messages as blue text on a
bright red background.
If either character is a "-" or is omitted, the corresponding color
is set to that of normal text.
.PP
An 8-bit color string is one or two decimal integers separated by a dot,
where the first integer specifies the foreground color and
the second specifies the background color.
Each integer is a value between 0 and 255 inclusive which selects
a "CSI 38;5" color value (see
.br
.nh
https://en.wikipedia.org/wiki/ANSI_escape_code#SGR_parameters)
.hy
If either integer is a "-" or is omitted,
the corresponding color is set to that of normal text.
On MS-DOS versions of
.IR less ,
8-bit color is not supported; instead, decimal values are interpreted as 4-bit
CHAR_INFO.Attributes values
(see
.br
.nh
https://docs.microsoft.com/en-us/windows/console/char-info-str).
.hy
.RE
.IP "\-e or \-\-quit-at-eof"
Causes
.I less
to automatically exit
the second time it reaches end-of-file.
By default, the only way to exit
.I less
is via the "q" command.
.IP "\-E or \-\-QUIT-AT-EOF"
Causes
.I less
to automatically exit the first time it reaches end-of-file.
.IP "\-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,
.I less
will refuse to open non-regular files.
Note that some operating systems will not allow directories
to be read, even if \-f is set.
.IP "\-F or \-\-quit-if-one-screen"
Causes
.I less
to automatically exit
if the entire file can be displayed on the first screen.
.IP "\-g or \-\-hilite-search"
Normally,
.I 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
.I less
to run somewhat faster than the default.
.IP "\-G or \-\-HILITE-SEARCH"
The \-G option suppresses all highlighting of strings found by search commands.
.IP "\-h\fIn\fP or \-\-max-back-scroll=\fIn\fP"
Specifies a maximum number of lines to scroll backward.
If it is necessary to scroll backward more than \fIn\fP lines,
the screen is repainted in a forward direction instead.
(If the terminal does not have the ability to scroll
backward, \-h0 is implied.)
.IP "\-i or \-\-ignore-case"
Causes searches to ignore case; that is,
uppercase and lowercase are considered identical.
This option is ignored if any uppercase letters
appear in the search pattern;
in other words,
if a pattern contains uppercase letters, then that search does not ignore case.
.IP "\-I or \-\-IGNORE-CASE"
Like \-i, but searches ignore case even if
the pattern contains uppercase letters.
.IP "\-j\fIn\fP or \-\-jump-target=\fIn\fP"
Specifies a line on the screen where the "target" line
is to be positioned.
The target line is the line specified by any command to
search for a pattern, jump to a line number,
jump to a file percentage or jump to a tag.
The screen line may be specified by a number: the top line on the screen
is 1, the next is 2, and so on.
The number may be negative to specify a line relative to the bottom
of the screen: the bottom line on the screen is \-1, the second
to the bottom is \-2, and so on.
Alternately, the screen line may be specified as a fraction of the height
of the screen, starting with a decimal point: \&.5 is in the middle of the
screen, \&.3 is three tenths down from the first line, and so on.
If the line is specified as a fraction, the actual line number
is recalculated if the terminal window is resized, so that the
target line remains at the 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.
.IP "\-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).
.IP "\-k\fIfilename\fP or \-\-lesskey-file=\fIfilename\fP"
Causes
.I less
to open and interpret the named file as a
.IR lesskey (1)
binary 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
.I lesskey
file.
.IP "\-\-lesskey-src=\fIfilename\fP"
Causes
.I less
to open and interpret the named file as a
.IR lesskey (1)
source file.
If the LESSKEYIN or LESSKEYIN_SYSTEM environment variable is set, or
if a lesskey source file is found in a standard place (see KEY BINDINGS),
it is also used as a
.I "lesskey source"
file.
Prior to version 582, the
.I lesskey
program needed to be run to convert a
.I "lesskey source"
file to a
.I "lesskey binary"
file for
.I less
to use.
Newer versions of
.I less
read the
.I "lesskey source"
file directly and ignore the binary file if the source file exists.
.IP "\-K or \-\-quit-on-intr"
Causes
.I less
to exit immediately (with status 2)
when an interrupt character (usually ^C) is typed.
Normally, an interrupt character causes
.I 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.
.IP "\-L or \-\-no-lessopen"
Ignore the LESSOPEN environment variable
(see the INPUT PREPROCESSOR section below).
This option can be set from within
.IR less ,
but it will apply only to files opened subsequently, not to the
file which is currently open.
.IP "\-m or \-\-long-prompt"
Causes
.I less
to prompt verbosely (like \fImore\fP),
with the percent into the file.
By default,
.I less
prompts with a colon.
.IP "\-M or \-\-LONG-PROMPT"
Causes
.I less
to prompt even more verbosely than
.IR more .
.IP "\-n or \-\-line-numbers"
Suppresses line numbers.
The default (to use line numbers) may cause
.I less
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).
.IP "\-N or \-\-LINE-NUMBERS"
Causes a line number to be displayed at the beginning of
each line in the display.
.IP "\-o\fIfilename\fP or \-\-log-file=\fIfilename\fP"
Causes
.I 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,
.I less
will ask for confirmation before overwriting it.
.IP "\-O\fIfilename\fP or \-\-LOG-FILE=\fIfilename\fP"
The \-O option is like \-o, but it will overwrite an existing
file without asking for confirmation.
.sp
If no log file has been specified,
the \-o and \-O options can be used from within
.I 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
.IR less .
.IP "\-p\fIpattern\fP or \-\-pattern=\fIpattern\fP"
The \-p option on the command line is equivalent to
specifying +/\fIpattern\fP;
that is, it tells
.I less
to start at the first occurrence of \fIpattern\fP in the file.
.IP "\-P\fIprompt\fP or \-\-prompt=\fIprompt\fP"
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
.I 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).
.sp 1
All prompt strings consist of a sequence of
letters and special escape sequences.
See the section on PROMPTS for more details.
.IP "\-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.
.IP "\-Q or \-\-QUIET or \-\-SILENT"
Causes totally "quiet" operation:
the terminal bell is never rung.
If the terminal has a "visual bell", it is used in all cases
where the terminal bell would have been rung.
.IP "\-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,
.I 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.
.sp
USE OF THE \-r OPTION IS NOT RECOMMENDED.
.IP "\-R or \-\-RAW-CONTROL-CHARS"
Like \-r, but only ANSI "color" escape sequences and OSC 8 hyperlink
sequences are output in "raw" form.
Unlike \-r, the screen appearance is maintained correctly,
provided that there are no escape sequences in the file
other than these types of escape sequences.
Color escape sequences are only supported when the color
is changed within one line, not across lines.
In other words, the beginning of each line is assumed to be
normal (non-colored), regardless of any escape sequences in previous lines.
For the purpose of keeping track of screen appearance,
these escape sequences are assumed to not move the cursor.
.sp
OSC 8 hyperlinks are sequences of the form:
.sp
ESC ] 8 ; \&...\& \\7
.sp
The terminating sequence may be either a BEL character (\\7)
or the two-character sequence "ESC \\".
.sp
ANSI color escape sequences are sequences of the form:
.sp
ESC [ \&...\& m
.sp
where the "...\&" is zero or more color specification characters.
You can make
.I 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
.I 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.
.IP "\-s or \-\-squeeze-blank-lines"
Causes consecutive blank lines to be squeezed into a single blank line.
This is useful when viewing
.I nroff
output.
.IP "\-S or \-\-chop-long-lines"
Causes lines longer than the screen width to be
chopped (truncated) rather than wrapped.
That is, the portion of a long line that does not fit in
the screen width is not displayed until you press RIGHT-ARROW.
The default is to wrap long lines; that is, display the remainder
on the next line.
.IP "\-t\fItag\fP or \-\-tag=\fItag\fP"
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
.IR ctags (1)
or an equivalent command.
If the environment variable LESSGLOBALTAGS is set, it is taken to be
the name of a command compatible with
.IR global (1),
and that command is executed to find the tag.
(See
.nh
https://www.gnu.org/software/global/global.html).
.hy
The \-t option may also be specified from within
.I less
(using the \- command) as a way of examining a new file.
The command ":t" is equivalent to specifying \-t from within
.IR less .
.IP "\-T\fItagsfile\fP or \-\-tag-file=\fItagsfile\fP"
Specifies a tags file to be used instead of "tags".
.IP "\-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.
.IP "\-U or \-\-UNDERLINE-SPECIAL"
Causes backspaces, tabs, carriage returns and "formatting characters"
(as defined by Unicode) to be treated as control characters;
that is, they are handled as specified by the \-r option.
.sp
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 capability.
Other backspaces are deleted, along with the preceding character.