


LESS(1)                                                   LESS(1)


NNAAMMEE
       less - opposite of more

SSYYNNOOPPSSIISS
       lleessss --??
       lleessss --VV
       lleessss [[--[[++]]aaBBccCCddeeEEffHHiimmMMnnNNqqQQrrssSSuuUUww]]
            [[--bb _b_u_f_s]] [[--hh _l_i_n_e_s]] [[--jj _l_i_n_e]] [[--kk _k_e_y_f_i_l_e]]
            [[--{{ooOO}} _l_o_g_f_i_l_e]] [[--pp _p_a_t_t_e_r_n]] [[--PP _p_r_o_m_p_t]] [[--tt _t_a_g]]
            [[--TT _t_a_g_f_i_l_e]] [[--xx _t_a_b]] [[--yy _l_i_n_e_s]] [[--[[zz]] _l_i_n_e_s]]
            [[++[[++]]_c_m_d]] [[_f_i_l_e_n_a_m_e]]......


DDEESSCCRRIIPPTTIIOONN
       _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.


CCOOMMMMAANNDDSS
       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.


       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



                                                                1





LESS(1)                                                   LESS(1)


              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.


       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.)


       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.)





                                                                2





LESS(1)                                                   LESS(1)


       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.   (This  works  if  standard
              input  is  being read, but only if _l_e_s_s has already
              read to the end of the file.  It  is  always  fast,
              but not always useful.)


       {      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.




                                                                3





LESS(1)                                                   LESS(1)


       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 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:

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

              *      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.

              @      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.


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



                                                                4





LESS(1)                                                   LESS(1)


              immediately before the top line displayed.

              Certain characters are special as in the / command:

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

              *      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.

              @      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.


       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 !, the search is made for the N-th line NOT
              containing the pattern.  If the previous search was
              modified by *, the search continues in the next (or
              previous) file if  not  satisfied  in  the  current
              file.   There  is  no effect if the previous search
              was modified by @.


       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 *.


       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



                                                                5





LESS(1)                                                   LESS(1)


              ESC-u  command,  turn  highlighting  back  on.  Any
              search command will also turn highlighting back on.
              (Highlighting  can also be disabled by toggling the
              -F flag; 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.   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.


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


       :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.


       = 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  below),  this will change the setting of that
              option and  print  a  message  describing  the  new



                                                                6





LESS(1)                                                   LESS(1)


              setting.   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 noth-
              ing is changed.


       -+     Followed by one of the command line option  letters
              (see  below),  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.


       --     Followed  by one of the command line option letters
              (see below), this will  reset  the  option  to  the
              "opposite"  of its default setting and print a mes-
              sage describing the new setting.  (The  "--_X"  com-
              mand  does  the  same  thing as "-_X" on the command
              line.)  This does not work for numeric  or  string-
              valued options.


       _      (Underscore.)   Followed by one of the command line
              option letters (see below), this will print a  mes-
              sage describing the current setting of that option.
              The setting of the option is not changed.


       +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 ZZ
              Exits _l_e_s_s_.

       The  following  three  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 EDITOR, or defaults to "vi".  See also the
              discussion of LESSEDIT under the section on PROMPTS
              below.





                                                                7





LESS(1)                                                   LESS(1)


       ! 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.  In
              all cases, the shell is taken from the  environment
              variable SHELL, or defaults to "sh".


       | <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.


OOPPTTIIOONNSS
       Command  line  options  are described below.  Most options
       may be changed while _l_e_s_s is running, via the "-" command.

       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

       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  on  the  command  line  by
       beginning the command line option with "-+".

       A  dollar  sign  ($)  may  be used to signal the end of an
       option string.  This is important only for options like -P
       which take a following string.

       -?     This  option  displays  a  summary  of the commands
              accepted by _l_e_s_s (the same as the h  command).   If
              this   option  is  given,  all  other  options  are
              ignored, and _l_e_s_s exits after the  help  screen  is
              viewed.   (Depending  on  how your shell interprets
              the question mark, it may be necessary to quote the
              question mark, thus: "-\?".)

       -a     Causes  searches  to  start  after  the  last  line



                                                                8





LESS(1)                                                   LESS(1)


              displayed on the screen, thus  skipping  all  lines
              displayed  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    Causes   _l_e_s_s  to  use  a  non-standard  number  of
              buffers.  Buffers are 1K, and by default 10 buffers
              are  used  (except  if data in coming from standard
              input; see the -B option).  The number _n  specifies
              a different number of buffers to use.

       -B     Disables  automatic  allocation of buffers, so that
              only the default number of buffers  are  used.   If
              more data is read than will fit in the buffers, the
              oldest data is discarded.  By default, when data is
              coming  from  standard input, buffers are allocated
              automatically as needed to avoid loss of data.

       -c     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     The -C option is like -c, but the screen is cleared
              before it is repainted.

       -d     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).

       -Dxx_c_o_l_o_r
              [MS-DOS only] Sets the color of the text displayed.
              x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.   _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     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     Causes _l_e_s_s to automatically exit the first time it
              reaches end-of-file.

       -f     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,  _l_e_s_s  will



                                                                9





LESS(1)                                                   LESS(1)


              refuse to open non-regular files.

       -F     Normally,  _l_e_s_s  will  highlight  all strings which
              match the current  search  pattern,  by  displaying
              them in standout mode.  The -F flag suppresses this
              highlighting.

       -h_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     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.

       -j_n    Specifies a line on the screen where "target" lines
              are to be positioned.  Target lines are the  object
              of  text  searches,  tag  searches, jumps to a line
              number, jumps to a file percentage, and jumps 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 immedi-
              ately 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.

       -k_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  a  file called .less exists in the
              user's home directory, this file is also used as  a
              _l_e_s_s_k_e_y file.

       -m     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     Causes  _l_e_s_s  to  prompt  even  more verbosely than
              _m_o_r_e_.

       -n     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 flag will
              avoid this problem.  Using line numbers means:  the
              line number will be displayed in the verbose prompt



                                                               10





LESS(1)                                                   LESS(1)


              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     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
              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
              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 _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
              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  occurence  of  _p_a_t_t_e_r_n  in  the
              file.

       -P_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.   -P
              followed  by  a  string changes the default (short)
              prompt to that string.  -Pm changes the medium (-m)
              prompt to the string, and -PM changes the long (-M)
              prompt.  Also, -P= changes the message  printed  by
              the  =  command  to  the  given string.  All prompt
              strings consist of a sequence of letters  and  spe-
              cial  escape sequences.  See the section on PROMPTS
              for more details.

       -q     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.



                                                               11





LESS(1)                                                   LESS(1)


       -Q     Causes totally "quiet" operation: the terminal bell
              is never rung.

       -r     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
              flag 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 charac-
              ter).   Thus,  various display problems may result,
              such as long lines being split in the wrong  place.

       -s     Causes  consecutive blank lines to be squeezed into
              a single blank line.  This is useful  when  viewing
              _n_r_o_f_f output.

       -S     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  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
              Specifies a tags file to be used instead of "tags".

       -u     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     Causes  backspaces  and  carriage  returns  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



                                                               12





LESS(1)                                                   LESS(1)


              are  handled  as  specified by the -r option.  Text
              which is overstruck or underlined can  be  searched
              for.

       -V     Displays the version number of _l_e_s_s_.

       -w     Causes  blank  lines  to be used to represent lines
              past the end of the  file.   By  default,  a  tilde
              character is used.

       -x_n    Sets  tab stops every _n positions.  The default for
              _n is 8.

       -X     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    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.

       -[z]_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.

       +      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
              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.






                                                               13





LESS(1)                                                   LESS(1)


LLIINNEE EEDDIITTIINNGG
       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 char to the left of the cursor, or can-
              cel the command if the command line is empty.

       DELETE or [ ESC-x ]
              Delete the char 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.

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

       TAB    Complete the partial filename to the  left  of  the



                                                               14





LESS(1)                                                   LESS(1)


              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
              filesnames.

       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.


KKEEYY BBIINNDDIINNGGSS
       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 file called ".less" in your home
       directory.  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  EDIT-
       ING).  See the _l_e_s_s_k_e_y manual page for more details.


IINNPPUUTT PPRREEPPRROOCCEESSSSOORR
       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.  To  set  up
       an  input preprocessor, set the LESSOPEN environment vari-
       able to a command line which will invoke your  input  pre-
       processor.  This command line should include one occurence
       of the string "%s", which will be replaced by the filename



                                                               15





LESS(1)                                                   LESS(1)


       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 occurences
       of the string "%s"; the first is replaced with the  origi-
       nal  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 _l_e_s_s view them directly (by giving _l_e_s_s  the  name  of
       the file without the .Z suffix):

       lessopen.sh:
            #! /bin/sh
            if [ -f "$1.Z" ]; then
                 uncompress -c $1.Z >$1.tmp
                 echo $1.tmp
            fi

       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 also accept the  file-
       name  either  with  or without the .Z suffix, or to accept
       other types of compressed files, and so on.


NNAATTIIOONNAALL CCHHAARRAACCTTEERR SSEETTSS
       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.




                                                               16





LESS(1)                                                   LESS(1)


       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  The default character set.  BS, TAB,  NL,  CR,  and
              formfeed  are  control  characters,  all chars with
              values between 127 and 255 are binary, and all oth-
              ers are normal.

       latin1 Selects  the  ISO 8859/1 character set.  latin-1 is
              the same as ASCII, except  characters  between  161
              and 255 are treated as normal characters.

       dos    Selects a character set appropriate for MS-DOS.

       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.)

       Setting LESSCHARDEF to "8bcccbcc18b95.b" is  the  same  as
       setting  LESSCHARSET  to  "ascii".  Setting LESSCHARDEF to
       "8bcccbcc18b95.33b." is the same as setting LESSCHARSET to
       "latin1".

       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.  If LESSBINFMT
       does  not  begin  with a "*", normal attribute is assumed.
       The remainder of LESSBINFMT is a string which may  include



                                                               17





LESS(1)                                                   LESS(1)


       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 sur-
       rounded by brackets.  The  default  if  no  LESSBINFMT  is
       specified is "*d<%X>".


PPRROOMMPPTTSS
       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.

       %E     Replaced by the name of the editor (from the EDITOR
              environment  variable).   See the discussion 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.

       %p_X    Replaced by the  percent  into  the  current  input
              file.  The line used is determined by the _X as with
              the %b option.

       %s     Same as %B.



                                                               18





LESS(1)                                                   LESS(1)


       %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.

       ?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
              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  of
              the specified line is known.

       ?s     Same as "?B".

       ?x     True if there is a next input file (that is, if the



                                                               19





LESS(1)                                                   LESS(1)


              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
       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) ..?ltline %lt?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) .?ltline %lt?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:




                                                               20





LESS(1)                                                   LESS(1)


            %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.


EENNVVIIRROONNMMEENNTT VVAARRIIAABBLLEESS
       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
              .less file).

       LANG   Language for determining the character set.

       LC_CTYPE
              Language for determining the character set.

       LESS   Flags which are passed to _l_e_s_s automatically.

       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.

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

       LESSHELP
              Name of the help file.

       LESSOPEN
              Command  line  to  invoke  the  (optional)   input-



                                                               21





LESS(1)                                                   LESS(1)


              preprocessor.

       LINES  Sets  the  number  of  lines  on the screen.  Takes
              precedence over the number of  lines  specified  by
              the TERM variable.

       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.


SSEEEE AALLSSOO
       lesskey(1)


WWAARRNNIINNGGSS
       The = command and prompts (unless changed  by  -P)  report
       the  line number of the line at the top of the screen, but
       the byte and percent of the line  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.

       If a line longer than the screen width is split  (folded),
       and  a  search matches text which straddles the split, the
       matching text will not be highlighted.  In certain  cases,
       patterns  beginning  with  a ^ may not be highlighted cor-
       rectly.  Patterns which include a TAB character may not be
       highlighted  correctly.   If  a search is done using the !
       operator for text NOT  matching  a  pattern,  the  strings
       which do match the pattern are highlighted.  In all cases,
       even if the highlighting is incorrect, the text will  nev-
       ertheless be found correctly by the search.


CCOOPPYYRRIIGGHHTT
       Copyright (c) 1984,1985,1989,1994  Mark Nudelman

















                                                               22


