less

LESS(1)                      General Commands Manual                     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 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.)

       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 forget all the
              other commands, remember this one.

       SPACE or ^V or f or ^F
              Scroll forward N lines, default one window (see option -z below).
              If N is more than the screen size, only the final screenful is
              displayed.  Warning: some systems use ^V as a special
              literalization character.

       z      Like SPACE, but if N is specified, it becomes the new window size.

       ESC-SPACE
              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.

       ESC-} or ^RIGHTARROW
              Scroll horizontally right to show the end of the longest displayed
              line.

       ESC-{ or ^LEFTARROW
              Scroll horizontally left back to the first column.

       r or ^R or ^L
              Repaint the screen.

       R      Repaint the screen, discarding any buffered input.  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 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, respectively.  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, respectively.  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
              respectively.  Marks are preserved when a new file is 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 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).

              Certain characters are special if entered at the beginning of the
              pattern; they modify the type of search rather than become part of
              the pattern:

              ^N or !
                     Search for lines which do NOT match the pattern.

              ^E or *
                     Search multiple files.  That is, if the search reaches the
                     END of the current file without finding a match, the search
                     continues in the next file in the command line list.

              ^F or @
                     Begin the search at the first line of the FIRST file in the
                     command line list, regardless of what is currently
                     displayed on the screen or the settings 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 containing the
              pattern.  The search starts at the last line displayed (but see
              the -a and -j options, which change this).

              Certain characters are special as in the / command:

              ^N or !
                     Search for lines which do NOT match the pattern.

              ^E or *
                     Search multiple files.  That is, if the search reaches the
                     beginning of the current file without finding a match, the
                     search continues in the previous file in the command line
                     list.

              ^F or @
                     Begin the search at the last line of the last file in the
                     command line list, regardless of what is currently
                     displayed on the screen or the settings of the -a or -j
                     options.

              ^K     As in forward searches.

              ^R     As in forward searches.

       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 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
              reminder 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.

       :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 message is printed.  If the option letter has a
              numeric value (such as -b or -h), or a string value (such as -P or
              -t), a new value may be entered after the option letter.  If no
              new value is entered, a message describing the current setting is
              printed and nothing is changed.

       --     Like the - command, but takes a long option name (see OPTIONS
              below) rather than a single option letter.  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" command does the same thing as "-+X"
              on the command line.)  This does not work for string-valued
              options.

       --+    Like the -+ command, but takes a long option name rather than a
              single option 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 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 initially display each
              file starting at the end rather than the beginning.

       V      Prints the version number of less being run.

       q or Q or :q or :Q or ZZ
              Exits less.

       The following four commands may or may not be valid, depending on your
       particular installation.

       v      Invokes an editor to edit the current file being viewed.  The
              editor is taken from the environment variable VISUAL if defined,
              or EDITOR if VISUAL is not defined, or defaults to "vi" if neither
              VISUAL nor EDITOR is defined.  See also the discussion of LESSEDIT
              under the section on PROMPTS below.

       ! shell-command
              Invokes a shell to run the shell-command given.  A percent sign
              (%) in the command is replaced by the name of the current file.  A
              pound sign (#) is replaced by the name of the previously examined
              file.  "!!" repeats the last shell command.  "!" with no shell
              command 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 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 variable.  If an option
       appears in the LESS variable, it can be reset to its default value on the
       command line by beginning the command line option with "-+".

       Some options like -k or -D require a string to follow the option letter.
       The string for that option is considered to end when a dollar sign ($) is
       found.  For example, you can set two -D options on MS-DOS like this:

       LESS="Dn9.1$Ds4.1"

       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 KB of buffer
              space is used for each file (unless the file is a pipe; see the -B
              option).  The -b option specifies instead that n kilobytes of
              buffer space should be used for each file.  If n is -1, buffer
              space is unlimited; that is, the entire file can be read into
              memory.

       -B or --auto-buffers
              By default, when data is read from a pipe, buffers are allocated
              automatically as needed.  If a large amount of data is read from
              the pipe, this can cause a large amount of memory to be allocated.
              The -B option disables this automatic allocation of buffers for
              pipes, so that only 64 KB (or the amount of space specified by the
              -b option) is used for the pipe.  Warning: use of -B can result in
              erroneous 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 otherwise 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 normal 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 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 uppercase letters, then that search does not ignore case.

       -I or --IGNORE-CASE
              Like -i, but searches ignore case even if the pattern contains
              uppercase letters.

       -jn or --jump-target=n
              Specifies a line on the screen where the "target" line is to be
              positioned.  The target line is the line specified by any command
              to search for a pattern, jump to a line number, jump to a file
              percentage or jump to a tag.  The screen line may be specified by
              a number: the top line on the screen is 1, the next is 2, and so
              on.  The number may be negative to specify a line relative to the
              bottom of the screen: the bottom line on the screen is -1, the
              second to the bottom is -2, and so on.  Alternately, the screen
              line may be specified as a fraction of the height of the screen,
              starting with a decimal point: .5 is in the middle of the screen,
              .3 is three tenths down from the first line, and so on.  If the
              line is specified as a fraction, the actual line number is
              recalculated if the terminal window is resized, 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.

       -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 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.

       -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 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 overwriting it.

       -Ofilename or --LOG-FILE=filename
              The -O option is like -o, but it will overwrite an existing file
              without asking for confirmation.

              If no log file has been specified, the -o and -O options can be
              used from within less to specify a log file.  Without a file name,
              they will simply report the name of the log file.  The "s" command
              is equivalent to specifying -o from within less.

       -ppattern or --pattern=pattern
              The -p option on the command line is equivalent to specifying
              +/pattern; that is, it tells less to start at the first occurrence
              of pattern in the file.

       -Pprompt or --prompt=prompt
              Provides a way to tailor the three prompt styles to your own
              preference.  This 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 for more details.

       -q or --quiet or --silent
              Causes moderately "quiet" operation: the terminal bell is not rung
              if an attempt is made to scroll past the end of the file or before
              the beginning of the file.  If the terminal has a "visual bell",
              it is used instead.  The bell will be rung on certain other
              errors, such as typing an invalid character.  The default is to
              ring the terminal bell in all such cases.

       -Q or --QUIET or --SILENT
              Causes totally "quiet" operation: the terminal bell is never rung.
              If the terminal has a "visual bell", it is used in all cases where
              the terminal bell would have been rung.

       -r or --raw-control-chars
              Causes "raw" control characters to be displayed.  The default is
              to display control characters using the caret notation; for
              example, a control-A (octal 001) is 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
              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.

       -s or --squeeze-blank-lines
              Causes consecutive blank lines to be squeezed into a single blank
              line.  This is useful when viewing nroff output.

       -S or --chop-long-lines
              Causes lines longer than the screen width to be chopped
              (truncated) rather than wrapped.  That is, the portion of a long
              line that does not fit in the screen width is not displayed until
              you press RIGHT-ARROW.  The default is to wrap long lines; that
              is, display the remainder on the next line.

       -ttag or --tag=tag
              The -t option, followed immediately by a TAG, will edit the file
              containing that tag.  For this to work, tag information must be
              available; for example, there may be a file in the current
              directory called "tags", which was previously built by ctags(1) or
              an equivalent command.  If the environment variable LESSGLOBALTAGS
              is set, it is taken to be the name of a command compatible with
              global(1), and that command is executed to find the tag.  (See
              http://www.gnu.org/software/global/global.html).  The -t option
              may also be 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 "formatting
              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 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.

       -V or --version
              Displays the version number of less.

       -w or --hilite-unread
              Temporarily highlights the first "new" line after a forward
              movement of a full page.  The first "new" line is the line
              immediately following the line previously at the bottom of the
              screen.  Also highlights the target line after a g or p 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 spacing as the last two.  For example, -x9,17 will
              set tabs at positions 9, 17, 25, 33, etc.  The default for n is 8.

       -X or --no-init
              Disables sending the termcap initialization and deinitialization
              strings to the terminal.  This is sometimes desirable if the
              deinitialization string does 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.

       -"cc or --quotes=cc
              Changes the filename quoting character.  This may be necessary if
              you are trying to name a file which contains both spaces and quote
              characters.  Followed by a single character, this changes the
              quote character to that character.  Filenames 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 command is
              executing, less will continue to display the contents of the
              original file despite its name change.  If --follow-name is
              specified, during an F command less will periodically attempt to
              reopen the file by name.  If the reopen succeeds and the file is a
              different file from the original (which means that a new file has
              been created with the same name as the original (now renamed)
              file), less will display the contents of that new file.

       --mouse
              Enables mouse input: scrolling the mouse wheel down moves forward
              in the file, scrolling the mouse wheel up moves backwards in the
              file, and clicking the mouse sets the "#" mark to the line where
              the mouse is clicked.  The number of lines to scroll when the
              wheel is moved can be set by the --wheel-lines option.  Mouse
              input works only on terminals which support X11 mouse reporting,
              and on the Windows version of less.

       --MOUSE
              Like --mouse, except the direction scrolled on mouse wheel
              movement is reversed.

       --no-keypad
              Disables sending the keypad initialization and deinitialization
              strings to the terminal.  This is sometimes useful if the keypad
              strings make the numeric keypad behave in an undesirable manner.

       --no-histdups
              This option changes the behavior so that if a search string or
              file name is typed in, and the same string is already in the
              history list, the existing copy is removed from the history list
              before the new one is added.  Thus, a given string will appear
              only once in the history list.  Normally, a string may appear
              multiple times.

       --rscroll
              This option changes the character used to mark truncated lines.
              It may begin with a two-character attribute indicator like
              LESSBINFMT does.  If there is no attribute indicator, standout is
              used.  If set to "-", truncated lines are not marked.

       --save-marks
              Save marks in the history file, so marks are retained across
              different invocations of less.

       --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.

       --wheel-lines=n
              Set the number of lines to scroll when the mouse wheel is scrolled
              and the --mouse or --MOUSE option is in effect.  The default is 1
              line.

       --     A command line argument of "--" marks the end of option arguments.
              Any arguments following this are interpreted as filenames.  This
              can be useful when viewing a file whose name begins with a "-" or
              "+".

       +      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 previously 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.

       ^LEFTARROW [ ESC-b or ESC-LEFTARROW ]
              (That is, CONTROL and LEFTARROW simultaneously.)  Move the cursor
              one word to the left.

       ^RIGHTARROW [ ESC-w or ESC-RIGHTARROW ]
              (That is, CONTROL and RIGHTARROW simultaneously.)  Move the cursor
              one word to the right.

       HOME [ ESC-0 ]
              Move the cursor to the beginning of the line.

       END [ ESC-$ ]
              Move the cursor to the end of the line.

       BACKSPACE
              Delete the character to the left of the cursor, or cancel the
              command if the 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 cursor.  If it
              matches more than one filename, the first match is entered into
              the command line.  Repeated TABs will cycle thru the other
              matching filenames.  If the completed filename is a directory, a
              "/" is appended to the filename.  (On MS-DOS 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.

       ^L     Complete the partial filename to the left of the cursor.  If it
              matches more than one filename, all matches are entered into the
              command line (if they fit).

       ^U (Unix and OS/2) or ESC (MS-DOS)
              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 /usr/local/etc/sysless.
       (However, if less was built with a different sysconf directory than
       /usr/local/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 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, 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 "$1" in
            *.Z) TEMPFILE=$(mktemp)
                 uncompress -c $1  >$TEMPFILE  2>/dev/null
                 if [ -s $TEMPFILE ]; then
                      echo $TEMPFILE
                 else
                      rm -f $TEMPFILE
                 fi
                 ;;
            esac

       lessclose.sh:
            #! /bin/sh
            rm $2

       To use these scripts, put them both where they can be executed and set
       LESSOPEN="lessopen.sh %s", and LESSCLOSE="lessclose.sh %s %s".  More
       complex LESSOPEN and LESSCLOSE scripts may be written to accept other
       types of compressed files, and so on.

       It is also possible to set up an input preprocessor to pipe the file data
       directly to less, rather than putting the data into a replacement file.
       This avoids the need to 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.  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 versions of less, if LESSOPEN
       starts with only one vertical bar, the exit status of the preprocessor is
       ignored.

       When an input pipe is used, a LESSCLOSE postprocessor can be used, but it
       is usually not necessary since there is no replacement file to clean up.
       In this case, the replacement file name passed to the LESSCLOSE
       postprocessor is "-".

       For compatibility with previous versions of less, the input preprocessor
       or pipe is not used if less is viewing standard input.  However, if the
       first character of LESSOPEN is a dash (-), the input preprocessor is used
       on standard input as well as other files.  In this case, the dash is not
       considered to be part of the preprocessor command.  If standard input is
       being viewed, the input preprocessor is passed a file name consisting of
       a single dash.  Similarly, if the first two characters of LESSOPEN are
       vertical bar and dash (|-) or two vertical bars and a dash (||-), the
       input pipe is used on standard input as well as other files.  Again, in
       this case the dash is not considered to be part of the input pipe
       command.

NATIONAL CHARACTER SETS
       There are 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 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:

       ascii  BS, TAB, NL, CR, and formfeed are control characters, all chars
              with values between 32 and 126 are normal, and all others are
              binary.

       iso8859
              Selects an ISO 8859 character set.  This is the same as ASCII,
              except characters between 160 and 255 are treated as normal
              characters.

       latin1 Same as iso8859.

       latin9 Same as iso8859.

       dos    Selects a character set appropriate for MS-DOS.

       ebcdic Selects an EBCDIC character set.

       IBM-1047
              Selects an EBCDIC character set used by OS/390 Unix Services.
              This is the EBCDIC analogue of latin1.  You get similar results by
              setting either LESSCHARSET=IBM-1047 or LC_CTYPE=en_US in your
              environment.

       koi8-r Selects a Russian character set.

       next   Selects a character set appropriate for NeXT computers.

       utf-8  Selects the UTF-8 encoding of the ISO 10646 character set.  UTF-8
              is special in that it supports multi-byte characters in the input
              file.  It is the only character set that supports multi-byte
              characters.

       windows
              Selects a character set appropriate for Microsoft Windows (cp
              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
                       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, invalid octets, and stray
       trailing octets) are displayed individually using LESSBINFMT so as to
       facilitate diagnostic of how the UTF-8 file is ill-formed.

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 specified by the -j option.

       %B     Replaced by the size of the current input file.

       %c     Replaced by the column number of the text appearing in the first
              column of the screen.

       %dX    Replaced by the page number of a line in the input file.  The line
              to be used is determined by the X, as with the %b option.

       %D     Replaced by the number of pages in the input file, or
              equivalently, the page number of the last line in the input file.

       %E     Replaced by the name of the editor (from the VISUAL environment
              variable, or the EDITOR environment variable if VISUAL is not
              defined).  See the discussion of the LESSEDIT feature below.

       %f     Replaced by the name of the current input file.

       %F     Replaced by the last component of the name of the current input
              file.

       %g     Replaced by the shell-escaped name of the current input file.
              This is useful when the expanded string will be used in a shell
              command, such as in LESSEDIT.

       %i     Replaced by the index of the current file in the list of input
              files.

       %lX    Replaced by the line number of a line in the input file.  The line
              to be used is determined by the X, as with the %b option.

       %L     Replaced by the line number of the last line in the input file.

       %m     Replaced by the total number of input files.

       %pX    Replaced by the percent into the current input file, based on byte
              offsets.  The line used is determined by the X as with the %b
              option.

       %PX    Replaced by the percent into the current input file, based on line
              numbers.  The line used is determined by the X as with the %b
              option.

       %s     Same as %B.

       %t     Causes any trailing spaces to be removed.  Usually used at the end
              of the string, but may appear anywhere.

       %T     Normally expands to the word "file".  However if viewing files via
              a tags list 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
       condition character, up to a period, are included in the prompt.  If the
       condition is false, such characters are not included.  A colon appearing
       between the question mark and the period can be used to establish an
       "ELSE": any characters between the colon and the period are included in
       the string if and only if the IF condition is false.  Condition
       characters (which follow a question mark) may be:

       ?a     True if any characters have been included in the prompt so far.

       ?bX    True if the byte offset of the specified line is known.

       ?B     True if the size of current input file is known.

       ?c     True if the text is horizontally shifted (%c is not zero).

       ?dX    True if the page number of the specified line is known.

       ?e     True if at end-of-file.

       ?f     True if there is an input filename (that is, if input is not a
              pipe).

       ?lX    True if the line number of the specified line is known.

       ?L     True if the line number of the last line in the file is known.

       ?m     True if there is more than one input file.

       ?n     True if this is the first prompt in a new input file.

       ?pX    True if the percent into the current input file, based on byte
              offsets, of the specified line is known.

       ?PX    True if the percent into the current input file, based on line
              numbers, of the specified line is known.

       ?s     Same as "?B".

       ?x     True if there is a next input file (that is, if the current input
              file is not the last one).

       Any characters other than the special ones (question mark, colon, period,
       percent, and backslash) become literally part of the prompt.  Any of the
       special characters may be 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 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.

       ?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\: %x.:
               ?pB%pB\%:byte %bB?s/%s...%t

       ?f%f .?n?m(%T %i of %m) ..?ltlines %lt-%lb?L/%L. :
               byte %bB?s/%s. .?e(END) ?x- Next\: %x.:?pB%pB\%..%t

       And here is the default message produced by the = command:

       ?f%f .?m(%T %i of %m) .?ltlines %lt-%lb?L/%L. .
               byte %bB?s/%s. ?e(END) :?pB%pB\%..%t

       The prompt expansion features are also used for another purpose: if an
       environment 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. %g

       Note that this expands to the editor name, followed by a + and the line
       number, followed by the shell-escaped file name.  If your editor does not
       accept the "+linenumber" syntax, or has other differences in invocation
       syntax, the LESSEDIT variable can be changed to modify this default.

SECURITY
       When the environment variable LESSSECURE is set to 1, less runs in a
       "secure" mode.  This means these features are disabled:

              !      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

                     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" command specification.  In this mode,
       less behaves differently in these ways:

       The -e option works differently.  If the -e option is not set, less
       behaves as if the -e option were set.  If the -e option is set, less
       behaves as if the -E option were set.

       The -m option works differently.  If the -m option is not set, the medium
       prompt is used, and it is prefixed with the string "--More--".  If the -m
       option is set, the short prompt is used.

       The -n option acts like the -z option.  The normal behavior of the -n
       option is 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 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.

       COLUMNS
              Sets the number of columns on the screen.  Takes precedence over
              the number of columns specified by the TERM variable.  (But if you
              have a windowing system which supports TIOCGWINSZ or WIOCGETD, the
              window system's idea of the screen size takes precedence over the
              LINES and COLUMNS environment variables.)

       EDITOR The name of the editor (used for the v command).

       HOME   Name of the user's home directory (used to find a lesskey file on
              Unix and OS/2 systems).

       HOMEDRIVE, HOMEPATH
              Concatenation of the HOMEDRIVE and HOMEPATH environment variables
              is the name of the user's home directory if the HOME variable is
              not set (only in the Windows version).

       INIT   Name of the user's init directory (used to find a lesskey file on
              OS/2 systems).

       LANG   Language for determining the character set.

       LC_CTYPE
              Language for determining the character set.

       LESS   Options which are passed to less automatically.

       LESSANSIENDCHARS
              Characters which may end an ANSI color escape sequence (default
              "m").

       LESSANSIMIDCHARS
              Characters which may appear between the ESC character and the end
              character in an ANSI color escape sequence (default
              "0123456789:;[?!"'#%()*+ ".

       LESSBINFMT
              Format for displaying non-printable, non-control characters.

       LESSCHARDEF
              Defines a character set.

       LESSCHARSET
              Selects a predefined character set.

       LESSCLOSE
              Command line to invoke the (optional) input-postprocessor.

       LESSECHO
              Name of the lessecho program (default "lessecho").  The lessecho
              program is needed to expand metacharacters, such as * and ?, in
              filenames on Unix systems.

       LESSEDIT
              Editor prototype string (used for the v command).  See discussion
              under PROMPTS.

       LESSGLOBALTAGS
              Name of the command used by the -t option to find global tags.
              Normally should be set to "global" if your system has the
              global(1) command.  If not set, global tags are not used.

       LESSHISTFILE
              Name of the history file used to remember search commands and
              shell commands 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 systems.

       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 "metacharacters" 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 SECURITY.

       LESSSEPARATOR
              String to be appended to a directory name in filename completion.

       LESSUTFBINFMT
              Format for displaying non-printable Unicode code points.

       LESS_IS_MORE
              Emulate the more(1) command.

       LINES  Sets the number of lines on the screen.  Takes precedence over the
              number of lines specified by the TERM variable.  (But if you have
              a windowing system which supports TIOCGWINSZ or WIOCGETD, the
              window system's idea of the screen size takes 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) 1984-2020  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.

AUTHOR
       Mark Nudelman
       Report bugs at https://github.com/gwsw/less/issues.
       For more information, see the less homepage at
       http://www.greenwoodsoftware.com/less.



                            Version 563: 13 Jun 2020                     LESS(1)