xref: /freebsd-9.3-release/contrib/less/less.man

LESS(1)                                                   LESS(1)


NNAAMMEE
       less - opposite of more

SSYYNNOOPPSSIISS
       lleessss --??
       lleessss ----hheellpp
       lleessss --VV
       lleessss ----vveerrssiioonn
       lleessss [[--[[++]]aaBBccCCddeeEEffggGGiiIImmMMnnNNqqQQrrssSSuuUUVVwwXX]]
            [[--bb _b_u_f_s]] [[--hh _l_i_n_e_s]] [[--jj _l_i_n_e]] [[--kk _k_e_y_f_i_l_e]]
            [[--{{ooOO}} _l_o_g_f_i_l_e]] [[--pp _p_a_t_t_e_r_n]] [[--PP _p_r_o_m_p_t]] [[--tt _t_a_g]]
            [[--TT _t_a_g_s_f_i_l_e]] [[--xx _t_a_b]] [[--yy _l_i_n_e_s]] [[--[[zz]] _l_i_n_e_s]]
            [[++[[++]]_c_m_d]] [[----]] [[_f_i_l_e_n_a_m_e]]......
       (See  the OPTIONS section for alternate option syntax with
       long option names.)


DDEESSCCRRIIPPTTIIOONN
       _L_e_s_s is a program similar to _m_o_r_e (1),  but  which  allows
       backward movement in the file as well as forward movement.
       Also, _l_e_s_s does not have to read  the  entire  input  file
       before  starting,  so  with large input files it starts up
       faster than text editors like _v_i (1).  _L_e_s_s  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 _m_o_r_e and _v_i_.  Commands may be
       preceded by a decimal number, called N in the descriptions
       below.  The number is used by some commands, as indicated.


CCOOMMMMAANNDDSS
       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.  Warn-
              ing: some systems use ^V as a  special  literaliza-
              tion 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



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LESS(1)                                                   LESS(1)


              it reaches end-of-file in the process.

       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.

       ESC-) or RIGHTARROW
              Scroll  horizontally  right  N  characters, default
              half the screen width (see the -#  option).   While
              the  text  is  scrolled,  it  acts as though the -S
              option (chop lines) were in effect.  Note  that  if
              you  wish  to enter a number N, you must use ESC-),
              not RIGHTARROW, because the arrow is taken to be  a
              line  editing  command  (see  the LINE EDITING sec-
              tion).

       ESC-( or LEFTARROW
              Scroll horizontally left N characters, default half
              the screen width (see the -# option).

       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



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LESS(1)                                                   LESS(1)


              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.)

       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.)

       p or % Go to a position N percent into the file.  N should
              be between 0 and 100.

       {      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,



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LESS(1)                                                   LESS(1)


              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 letter, marks the current
              position with that letter.

       '      (Single  quote.)  Followed by any lowercase 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.

       /pattern
              Search  forward  in the file for the N-th line con-
              taining the pattern.  N defaults to 1.  The pattern
              is  a regular expression, as recognized by _e_d_.  The
              search starts at the second 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 pat-
                     tern.

              ^E or *
                     Search multiple  files.   That  is,  if  the
                     search  reaches  the END of the current file
                     without finding a match, the search  contin-
                     ues  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, regard-
                     less 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 metachar-
                     acters;   that   is,  do  a  simple  textual



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LESS(1)                                                   LESS(1)


                     comparison.

       ?pattern
              Search backward in the file for the N-th line  con-
              taining the pattern.  The search starts at the line
              immediately before the top line displayed.

              Certain characters are special as in the / command:

              ^N or !
                     Search for lines which do NOT match the pat-
                     tern.

              ^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 com-
                     mand line list.

              ^F or @
                     Begin the search at the  last  line  of  the
                     last  file in the command line list, regard-
                     less 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 modi-
              fied 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 direc-
              tion.

       ESC-n  Repeat previous search, but  crossing  file  bound-
              aries.   The  effect  is  as if the previous search
              were modified by *.



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LESS(1)                                                   LESS(1)


       ESC-N  Repeat previous search, but in the  reverse  direc-
              tion 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.)

       :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 pre-
              viously examined file.   However,  two  consecutive
              percent  signs  are  simply  replaced with a single
              percent sign.  This allows you to enter a  filename
              that  contains  a  percent sign in the name.  Simi-
              larly, two consecutive  pound  signs  are  replaced
              with a single pound sign.  The filename is inserted
              into the command line list of files so that it  can
              be  seen  by subsequent :n and :p commands.  If the
              filename consists of several files,  they  are  all
              inserted  into  the list of files and the first one
              is examined.  If the filename contains one or  more
              spaces,  the  entire filename should be enclosed in
              double quotes (also see the -" option).

       ^X^V or E
              Same as :e.  Warning: some systems use ^V as a spe-
              cial  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.

       = or ^G or :f
              Prints  some  information  about  the  file   being



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LESS(1)                                                   LESS(1)


              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  imme-
              diately  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  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 describ-
              ing the current setting of that option.   The  set-
              ting of the option is not changed.

       __     (Double  underscore.)  Like the _ (underscore) com-
              mand, but takes a long option name  rather  than  a
              single  option letter.  You must press RETURN after
              typing the option name.




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LESS(1)                                                   LESS(1)


       +cmd   Causes the specified cmd to be executed each time a
              new  file is examined.  For example, +G causes _l_e_s_s
              to initially display each file starting at the  end
              rather than the beginning.

       V      Prints the version number of _l_e_s_s being run.

       q or Q or :q or :Q or ZZ
              Exits _l_e_s_s_.

       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 environ-
              ment variable SHELL, or defaults to "sh".   On  MS-
              DOS  and OS/2 systems, the shell is the normal com-
              mand 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
              first  line  on the current screen and the position
              marked by the letter.  <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.


OOPPTTIIOONNSS
       Command  line  options  are described below.  Most options
       may be changed while _l_e_s_s 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



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LESS(1)                                                   LESS(1)


       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 capital-
       ized; 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 _l_e_s_s is invoked, you might tell _c_s_h_:

       setenv LESS "-options"

       or if you use _s_h_:

       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 environ-
       ment variable.  If an option appears in the LESS variable,
       it  can  be reset to its default value on the command line
       by beginning the command line option with "-+".

       For options like -P or -D which take a following string, a
       dollar  sign  ($)  must  be  used to signal the end of the
       string.  For example, to set two -D options on MS-DOS, you
       must have a dollar sign between them, like this:

       LESS="-Dn9.1$-Ds4.1"


       -? or --help
              This  option  displays  a  summary  of the commands
              accepted by _l_e_s_s  (the  same  as  the  h  command).
              (Depending  on  how your shell interprets the ques-
              tion mark, it may be necessary to quote  the  ques-
              tion mark, thus: "-\?".)

       -a or --search-skip-screen
              Causes  searches  to start after the last line dis-
              played on the screen, thus skipping all lines  dis-
              played  on  the screen.  By default, searches start
              at the second line on the screen (or after the last
              found line; see the -j option).

       -b_n or --buffers=_n
              Specifies  the  number of buffers _l_e_s_s will use for
              each file.  Buffers  are  1K,  and  by  default  10



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LESS(1)                                                   LESS(1)


              buffers  are used for each file (except if the file
              is a pipe; see the -B option).  The number _n speci-
              fies a different number of buffers to use.

       -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  the  number  of
              buffers specified by the -b option are used.  Warn-
              ing: use of -B can  result  in  erroneous  display,
              since  only  the  most  recently viewed part of the
              file 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
              The -C option is like -c, but the screen is cleared
              before it is repainted.

       -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 _l_e_s_s on a
              dumb terminal).

       -Dxx_c_o_l_o_r or --color=xx_c_o_l_o_r
              [MS-DOS only] Sets the color of the text displayed.
              xx is a single character which selects the  type  of
              text  whose  color is being set: n=normal, s=stand-
              out, d=bold, u=underlined,  k=blink.   _c_o_l_o_r  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_._0.

       -e or --quit-at-eof
              Causes _l_e_s_s to automatically exit the  second  time
              it  reaches  end-of-file.  By default, the only way
              to exit _l_e_s_s is via the "q" command.

       -E or --QUIT-AT-EOF
              Causes _l_e_s_s to automatically exit the first time it
              reaches end-of-file.





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LESS(1)                                                   LESS(1)


       -f or --force
              Forces non-regular files to be opened.  (A non-reg-
              ular file is a directory or a device special file.)
              Also  suppresses  the warning message when a binary
              file is opened.  By default, _l_e_s_s  will  refuse  to
              open non-regular files.

       -F or --quit-if-one-screen
              Causes  _l_e_s_s  to  automatically  exit if the entire
              file can be displayed on the first screen.

       -g or --hilite-search
              Normally, _l_e_s_s will  highlight  ALL  strings  which
              match  the  last  search  command.   The  -g option
              changes this behavior to highlight only the partic-
              ular string which was found by the last search com-
              mand.  This can cause _l_e_s_s to run  somewhat  faster
              than the default.

       -G or --HILITE-SEARCH
              The   -G  option  suppresses  all  highlighting  of
              strings found by search commands.

       -h_n or ---max-back-scroll=_n
              Specifies a maximum number of lines to scroll back-
              ward.   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 pat-
              tern contains uppercase letters.

       -j_n or --jump-target=_n
              Specifies a line on the screen where  the  "target"
              line  is  to  be  positioned.  A target line is the
              object of a text search, tag search, jump to a line
              number,  jump  to  a  file percentage, or jump to a
              marked position.  The screen line is 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.  If the -j
              option  is  used,  searches  begin  at   the   line



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LESS(1)                                                   LESS(1)


              immediately after the target line.  For example, if
              "-j4" is used, the target line is the  fourth  line
              on  the screen, so searches begin at the fifth line
              on the screen.

       -J or --status-column
              Displays a status column at the left  edge  of  the
              screen.   The  status column is used only if the -w
              or -W option is in effect.

       -k_f_i_l_e_n_a_m_e or --lesskey-file=_f_i_l_e_n_a_m_e
              Causes _l_e_s_s to open and interpret the named file as
              a  _l_e_s_s_k_e_y  (1)  file.   Multiple -k options may be
              specified.  If the LESSKEY or LESSKEY_SYSTEM  envi-
              ronment  variable  is  set, or if a lesskey file is
              found in a standard place (see KEY BINDINGS), it is
              also used as a _l_e_s_s_k_e_y file.

       -m or --long-prompt
              Causes  _l_e_s_s  to prompt verbosely (like _m_o_r_e), with
              the  percent  into  the  file.   By  default,  _l_e_s_s
              prompts with a colon.

       -M or --LONG-PROMPT
              Causes  _l_e_s_s  to  prompt  even  more verbosely than
              _m_o_r_e_.

       -n or --line-numbers
              Suppresses line numbers.  The default (to use  line
              numbers)  may cause _l_e_s_s 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  begin-
              ning of each line in the display.

       -o_f_i_l_e_n_a_m_e or --log-file=_f_i_l_e_n_a_m_e
              Causes  _l_e_s_s 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, _l_e_s_s will ask for confirmation
              before overwriting it.

       -O_f_i_l_e_n_a_m_e or --LOG-FILE=_f_i_l_e_n_a_m_e
              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



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LESS(1)                                                   LESS(1)


              options  can  be used from within _l_e_s_s 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 _l_e_s_s_.

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

       -P_p_r_o_m_p_t or --prompt=_p_r_o_m_p_t
              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  _l_e_s_s  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.  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.

       -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,  _l_e_s_s  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.





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LESS(1)                                                   LESS(1)


       -R or --RAW-CONTROL-CHARS
              Like  -r,  but  tries  to  keep track of the screen
              appearance where possible.  This works only if  the
              input  consists  of  normal  text and possibly some
              ANSI "color" escape sequences, which are  sequences
              of the form:

                   ESC [ ... m

              where  the  "..."  is zero or more characters other
              than "m".  For the  purpose  of  keeping  track  of
              screen  appearance,  all control characters and all
              ANSI color escape sequences are assumed to not move
              the  cursor.   You can make _l_e_s_s think that charac-
              ters 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.

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

       -S or --chop-long-lines
              Causes  lines  longer  than  the screen width to be
              chopped rather than folded.  That is, the remainder
              of a long line is simply discarded.  The default is
              to fold long lines; that is, display the  remainder
              on the next line.

       -t_t_a_g or --tag=_t_a_g
              The  -t option, followed immediately by a TAG, will
              edit the file containing that  tag.   For  this  to
              work,  there  must  be  a file called "tags" in the
              current directory, which was  previously  built  by
              the  _c_t_a_g_s  (1)  command.   This option may also be
              specified from within _l_e_s_s (using the - command) as
              a way of examining a new file.  The command ":t" is
              equivalent to specifying -t from within _l_e_s_s_.

       -T_t_a_g_s_f_i_l_e or --tag-file=_t_a_g_s_f_i_l_e
              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 and carriage returns to  be
              treated  as  control  characters; that is, they are
              handled as specified by the -r option.




                     Version 358: 08 Jul 2000                  14





LESS(1)                                                   LESS(1)


              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 _l_e_s_s_.

       -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 high-
              lights 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.

       -x_n or --tabs=_n
              Sets  tab stops every _n positions.  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.

       -y_n or --max-forw-scroll=_n
              Specifies a maximum number of lines to scroll  for-
              ward.   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.





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LESS(1)                                                   LESS(1)


       -[z]_n or --window=_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  _m_o_r_e_.   If the number _n is negative, it indi-
              cates _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 automati-
              cally changes to 36 lines.

       -"_c_c or --quotes=_c_c
              Changes the filename quoting character.   This  may
              be necessary if you are trying to name a file which
              contains both spaces and  quote  characters.   Fol-
              lowed 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  char-
              acter.  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  com-
              mands.   If  the  number specified is zero, it sets
              the default number of positions to one half of  the
              screen width.

       --     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 remain-
              der of that option is taken to be an  initial  com-
              mand  to _l_e_s_s_.  For example, +G tells _l_e_s_s 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 dis-
              play at the specified line number (however, see the
              caveat under the "g" command above).  If the option



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LESS(1)                                                   LESS(1)


              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.


LLIINNEE EEDDIITTIINNGG
       When entering command line at the  bottom  of  the  screen
       (for  example,  a filename for the :e command, or the pat-
       tern for a search command), certain keys can  be  used  to
       manipulate the command line.  Most commands have an alter-
       nate form in [ brackets ] which can be used if a key  does
       not  exist on a particular keyboard.  (The bracketed forms
       do not work in the MS-DOS version.)  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.




                     Version 358: 08 Jul 2000                  17





LESS(1)                                                   LESS(1)


       UPARROW [ ESC-k ]
              Retrieve the previous command line.

       DOWNARROW [ ESC-j ]
              Retrieve the next command line.

       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 direc-
              tory, 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) or ESC (MS-DOS)
              Delete the entire command line, or cancel the  com-
              mand  if  the  command  line is empty.  If you have
              changed your line-kill character in Unix  to  some-
              thing other than ^U, that character is used instead
              of ^U.


KKEEYY BBIINNDDIINNGGSS
       You may define your own _l_e_s_s commands by using the program
       _l_e_s_s_k_e_y (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 _l_e_s_s_k_e_y to change the line-editing
       keys (see LINE EDITING), and to set environment variables.
       If the environment variable LESSKEY is set, _l_e_s_s uses that
       as the name of the lesskey file.  Otherwise, _l_e_s_s looks in
       a  standard  place  for the lesskey file: On Unix systems,
       _l_e_s_s looks for a lesskey file  called  "$HOME/.less".   On
       MS-DOS  and Windows systems, _l_e_s_s looks for a lesskey file
       called "$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  sys-
       tems,    _l_e_s_s    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 _l_e_s_s_k_e_y manual page for more details.



                     Version 358: 08 Jul 2000                  18





LESS(1)                                                   LESS(1)


       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,
       _l_e_s_s uses that as the  name  of  the  system-wide  lesskey
       file.   Otherwise,  _l_e_s_s looks in a standard place for the
       system-wide lesskey file: On Unix systems, the system-wide
       lesskey  file  is  /usr/local/bin/.sysless.   (However, if
       _l_e_s_s was built with  a  different  binary  directory  than
       /usr/local/bin,  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.


IINNPPUUTT PPRREEPPRROOCCEESSSSOORR
       You may define an "input preprocessor" for  _l_e_s_s_.   Before
       _l_e_s_s  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,  _l_e_s_s  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 file-
       name,  _l_e_s_s  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 environ-
       ment 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 _l_e_s_s 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 origi-
       nal name of the file and the second with the name  of  the



                     Version 358: 08 Jul 2000                  19





LESS(1)                                                   LESS(1)


       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 _l_e_s_s view them directly:

       lessopen.sh:
            #! /bin/sh
            case "$1" in
            *.Z) uncompress -c $1  >/tmp/less.$$  2>/dev/null
                 if [ -s /tmp/less.$$ ]; then
                      echo /tmp/less.$$
                 else
                      rm -f /tmp/less.$$
                 fi
                 ;;
            esac

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

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

       It  is  also  possible  to set up an input preprocessor to
       pipe the file data directly to _l_e_s_s_, 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
       _l_e_s_s  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 pre-
       processor is an input pipe.

       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
                 ;;
            esac

       To  use  this  script, put it where it can be executed and



                     Version 358: 08 Jul 2000                  20





LESS(1)                                                   LESS(1)


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


NNAATTIIOONNAALL CCHHAARRAACCTTEERR SSEETTSS
       There are three types of characters in the input file:

       normal characters
              can be displayed directly to the screen.

       control characters
              should not be displayed directly, but are  expected
              to  be  found  in  ordinary  text  files  (such  as
              backspace and tab).

       binary characters
              should  not  be  displayed  directly  and  are  not
              expected to be found in text files.

       A "character set" is simply a description of which charac-
       ters are to be considered  normal,  control,  and  binary.
       The LESSCHARSET environment variable may be used to select
       a character set.  Possible values for LESSCHARSET are:

       ascii  BS, TAB, NL, CR, and formfeed are  control  charac-
              ters,  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.

       dos    Selects a character set appropriate for MS-DOS.

       ebcdic Selects an EBCDIC character set.

       koi8-r Selects a Russian character set.

       next   Selects a character set appropriate for  NeXT  com-
              puters.

       utf-8  Selects the UTF-8 encoding of the ISO 10646 charac-
              ter set.

       If the LESSCHARSET environment variable is  not  set,  the
       default  character  set is latin1.  However, if the string
       "UTF-8" is found in the LC_ALL, LC_CTYPE or LANG  environ-
       ment  variables,  then  the default character set is utf-8



                     Version 358: 08 Jul 2000                  21





LESS(1)                                                   LESS(1)


       instead.

       In special cases, it may be desired to tailor _l_e_s_s to  use
       a  character  set  other  than the ones definable by LESS-
       CHARSET.  In this case,  the  environment  variable  LESS-
       CHARDEF  can be used to define a character set.  It should
       be set to a string where each character in the string rep-
       resents 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 repeti-
       tion.  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 neces-
       sarily represent any real character set.)

       This table shows the value of LESSCHARDEF which is equiva-
       lent 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.
            iso8859   8bcccbcc18b95.33b.
            koi8-r    8bcccbcc18b95.b128.
            latin1    8bcccbcc18b95.33b.
            next      8bcccbcc18b95.bb125.bb

       If neither LESSCHARSET nor LESSCHARDEF is  set,  but  your
       system  supports  the  _s_e_t_l_o_c_a_l_e  interface, _l_e_s_s will use
       setlocale to determine the character  set.   setlocale  is
       controlled  by  setting  the  LANG or LC_CTYPE environment
       variables.

       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 vari-
       able.   LESSBINFMT  may begin with a "*" and one character
       to select the display attribute: "*k" is blinking, "*d" is
       bold,  "*u"  is  underlined, "*s" is standout, and "*n" is
       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 LESS-
       BINFMT is "*u[%x]", binary  characters  are  displayed  in
       underlined   hexadecimal   surrounded  by  brackets.   The
       default if no LESSBINFMT is specified is "*s<%X>".





                     Version 358: 08 Jul 2000                  22





LESS(1)                                                   LESS(1)


PPRROOMMPPTTSS
       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  ordi-
       nary  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:

       %b_X    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.

       %d_X    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  dis-
              cussion of the LESSEDIT feature below.

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

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

       %l_X    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.




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LESS(1)                                                   LESS(1)


       %p_X    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.

       %P_X    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  any-
              where.

       %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 sin-
       gle  character acts like an "IF": depending on the follow-
       ing 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.

       ?b_X    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).

       ?d_X    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).

       ?l_X    True if the line number of the  specified  line  is



                     Version 358: 08 Jul 2000                  24





LESS(1)                                                   LESS(1)


              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.

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

       ?P_X    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 file-
       name is followed by the line number, if  known,  otherwise
       the  percent if known, otherwise the byte offset if known.
       Otherwise, a dash is printed.  Notice  how  each  question
       mark has a matching period, and how the % after the %pt is
       included literally by escaping it with a backslash.

       ?n?f%f .?m(file %i of %m) ..?e(END) ?x- Next\: %x..%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 refer-
       ence, here are the defaults for the other two prompts  (-m



                     Version 358: 08 Jul 2000                  25





LESS(1)                                                   LESS(1)


       and  -M respectively).  Each is broken into two lines here
       for readability only.

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

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

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

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

       The  prompt  expansion  features are also used for another
       purpose: if an environment variable LESSEDIT  is  defined,
       it  is  used as the command to be executed when the v com-
       mand is invoked.  The LESSEDIT string is expanded  in  the
       same  way  as  the  prompt strings.  The default value for
       LESSEDIT is:

            %E ?lm+%lm. %f

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


SSEECCUURRIITTYY
       When the environment variable LESSSECURE is set to 1, _l_e_s_s
       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"



                     Version 358: 08 Jul 2000                  26





LESS(1)                                                   LESS(1)


       mode.


EENNVVIIRROONNMMEENNTT VVAARRIIAABBLLEESS
       Environment  variables may be specified either in the sys-
       tem environment as usual, or in a _l_e_s_s_k_e_y  (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 systems).

       HOMEDRIVE, HOMEPATH
              Concatenation of the HOMEDRIVE and  HOMEPATH  envi-
              ronment  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 _l_e_s_s automatically.

       LESSANSIENDCHARS
              Characters which are assumed to end an  ANSI  color
              escape sequence (default "m").

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

       LESSCHARDEF
              Defines a character set.





                     Version 358: 08 Jul 2000                  27





LESS(1)                                                   LESS(1)


       LESSCHARSET
              Selects a predefined character set.

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

       LESSECHO
              Name  of the lessecho program (default "lessecho").
              The lessecho program is needed to expand  metachar-
              acters,  such as * and ?, in filenames on Unix sys-
              tems.

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

       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 "metachar-
              acters" by the shell.

       LESSMETAESCAPE
              Prefix which less will add before each  metacharac-
              ter  in  a  command  sent  to  the shell.  If LESS-
              METAESCAPE is an empty string, commands  containing
              metacharacters will not be passed to the shell.

       LESSOPEN
              Command line to invoke the (optional) input-prepro-
              cessor.

       LESSSECURE
              Runs less in "secure" mode.  See  discussion  under
              SECURITY.

       LESSSEPARATOR
              String  to be appended to a directory name in file-
              name completion.

       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.)

       PATH   User's search path (used to find a lesskey file  on



                     Version 358: 08 Jul 2000                  28





LESS(1)                                                   LESS(1)


              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 _l_e_s_s is being run.

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


SSEEEE AALLSSOO
       lesskey(1)


WWAARRNNIINNGGSS
       The = command and prompts (unless changed  by  -P)  report
       the line numbers of the lines at the top and bottom of the
       screen, but the byte and percent of the line after the one
       at the bottom of the screen.

       If  the :e command is used to name more than one file, and
       one of the named files has been viewed previously, the new
       files may be entered into the list in an unexpected order.

       On certain older terminals (the so-called  "magic  cookie"
       terminals),  search  highlighting  will cause an erroneous
       display.  On such terminals, search highlighting  is  dis-
       abled by default to avoid possible problems.

       In  certain cases, when search highlighting is enabled and
       a search pattern begins with  a  ^,  more  text  than  the
       matching  string  may  be highlighted.  (This problem does
       not occur when less is compiled to use the  POSIX  regular
       expression package.)

       On  some systems, _s_e_t_l_o_c_a_l_e claims that ASCII characters 0
       thru 31 are control characters rather than binary  charac-
       ters.   This  causes  _l_e_s_s  to  treat some binary files as
       ordinary, non-binary files.  To workaround  this  problem,
       set  the  environment  variable LESSCHARSET to "ascii" (or
       whatever character set is appropriate).

       See http://www.flash.net/~marknu/less for the latest  list
       of known bugs in this version of less.


CCOOPPYYRRIIGGHHTT
       Copyright (C) 2000  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



                     Version 358: 08 Jul 2000                  29





LESS(1)                                                   LESS(1)


       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 war-
       ranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR  PUR-
       POSE.   See  the  GNU  General  Public  License  for  more
       details.


AAUUTTHHOORR
       Mark Nudelman <marknu@flash.net>
       Send bug reports or comments to the above  address  or  to
       bug-less@gnu.org.






































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