LESS(1)								      LESS(1)



NAME
  less - opposite of more

SYNOPSIS
  less -?
  less [-[+]aBcCdeEfHimMnNqQrsSuUw]
       [-b bufs] [-h lines] [-j line] [-k keyfile]
       [-{oO} logfile] [-p pattern] [-P prompt] [-t tag]
       [-T tagfile] [-x tab] [-y lines] [-[z] lines]
       [+[+]cmd] [filename]...


DESCRIPTION
  Less is a program similar to more (1), but which allows backward movement
  in the file as well as forward movement.  Also, less does not have to read
  the entire input file before starting, so with large input files it starts
  up faster than text editors like vi (1).  Less uses termcap (or terminfo on
  some systems), so it can run on a variety of terminals.  There is even lim-
  ited support for hardcopy terminals.	(On a hardcopy terminal, lines which
  should be printed at the top of the screen are prefixed with a caret.)

  Commands are based on both more and vi. Commands may be preceded by a
  decimal number, called N in the descriptions below.  The number is used by
  some commands, as indicated.


COMMANDS
  In the following descriptions, ^X means control-X.  ESC stands for the
  ESCAPE key; for example ESC-v means the two character sequence "ESCAPE",
  then "v".

  h or H
       Help: display a summary of these commands.  If you forget all the
       other commands, remember this one.

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

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

  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.

  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 grow-
       ing 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.  (This works if standard input is being read, but only if less
       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.

  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 bot-
       tom 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 posi-
       tion 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 containing the pattern.
       N defaults to 1.	 The pattern is a regular expression, as recognized
       by ed. 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 pat-
       tern; they modify the type of search rather than become part of the
       pattern:

       ! Search for lines which do NOT match the pattern.

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

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

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

       Certain characters are special as in the / command:

       ! Search for lines which do NOT match the pattern.

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

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

  ESC-/pattern
       Same as "/*".

  ESC-?pattern
       Same as "?*".

  n    Repeat previous search, for N-th line containing the last pattern.  If
       the previous search was modified by !, 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 direction.

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

  ESC-N
       Repeat previous search, but in the reverse direction and crossing file
       boundaries.

  ESC-u
       Undo search highlighting.  Turn off highlighting of strings matching
       the current search pattern. If highlighting is already off because of
       a previous ESC-u command, turn highlighting back on.  Any search com-
       mand 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 com-
       mand line is re-examined.  A percent sign (%) in the filename is
       replaced by the name of the current file. A pound sign (#) is replaced
       by the name of the previously examined file.  The filename is inserted
       into the command line list of files so that it can be seen by subse-
       quent :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 special 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 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 mes-
       sage describing the current setting is printed and nothing 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 message describing the new setting.  (The "--X" command 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 message 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 exam-
       ined.  For example, +G causes less to initially display each file
       starting at the end rather than the beginning.

  V    Prints the version number of less being run.

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

  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.

  ! 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 environ-
       ment variable SHELL, or defaults to "sh".

  |  shell-command
        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.   may also be ^ or $ to indicate beginning or end of
       file respectively.  If  is . or newline, the current screen is
       piped.

OPTIONS
  Command line options are described below.  Most options may be changed
  while less is running, via the "-" command.

  Options are also taken from the environment variable "LESS".	For example,
  to avoid typing "less -options ..." each time less is invoked, you might
  tell csh:

  setenv LESS "-options"

  or if you use sh:

  LESS="-options"; export LESS

  The environment variable is parsed before the command line, so command line
  options override the LESS environment variable.  If an option appears in
  the LESS variable, it can be reset to its default 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 less (the
       same as the h command).	If this option is given, all other options
       are ignored, and less 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 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).

  -bn  Causes less 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 dif-
       ferent 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 com-
       ing 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 less on a dumb terminal).

  -Dxcolor
       [MS-DOS only] Sets the color of the text displayed.  x is a single
       character which selects the type of text whose color is being set:
       n=normal, s=standout, d=bold, u=underlined, k=blink.  color is a pair
       of numbers separated by a period. The first number selects the fore-
       ground color and the second selects the background color of the text.
       A single number N is the same as N.0.

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

  -E   Causes less 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 mes-
       sage when a binary file is opened.  By default, less will refuse to
       open non-regular files.

  -F   Normally, less will highlight all strings which match the current
       search pattern, by displaying them in standout mode.  The -F flag
       suppresses this highlighting.

  -hn  Specifies a maximum number of lines to scroll backward.	If it is
       necessary to scroll backward more than n lines, the screen is
       repainted in a forward direction instead.  (If the terminal does not
       have the ability to scroll backward, -h0 is implied.)

  -i   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.

  -jn  Specifies a line on the screen where "target" lines are to be posi-
       tioned.	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.

  -kfilename
       Causes less to open and interpret the named file as a lesskey (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 less-
       key file.

  -m   Causes less to prompt verbosely (like more), with the percent into the
       file.  By default, less prompts with a colon.

  -M   Causes less to prompt even more verbosely than more.

  -n   Suppresses line numbers.	 The default (to use line numbers) may cause
       less to run more slowly in some cases, especially with a very large
       input file.  Suppressing line numbers with the -n flag 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   Causes a line number to be displayed at the beginning of each line in
       the display.

  -ofilename
       Causes less to copy its input to the named file as it is being viewed.
       This applies only when the input file is a pipe, not an ordinary file.
       If the file already exists, less will ask for confirmation before
       overwriting it.

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

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

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

  -Pprompt
       Provides a way to tailor the three prompt styles to your own prefer-
       ence.  This option would normally be put in the LESS environment vari-
       able, rather than being typed in with each less command.	 Such an
       option must either be the last option in the LESS variable, or be ter-
       minated 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 special 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.

  -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, less cannot keep track of the actual appearance of the screen
       (since this depends on how the screen responds to each type of control
       character).  Thus, various display problems may result, such as long
       lines being split in the wrong place.

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

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

  -Ttagsfile
       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 char-
       acters; 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 under-
       lined text is displayed using the terminal's hardware underlining
       capability.  Also, backspaces which appear between two identical char-
       acters 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 immedi-
       ately 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.

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

  -xn  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 deini-
       tialization string does something unnecessary, like clearing the
       screen.

  -yn  Specifies a maximum number of lines to scroll forward.  If it is
       necessary to scroll forward more than n lines, the screen is repainted
       instead.	 The -c or -C option may be used to repaint from the top of
       the screen if desired.  By default, any forward movement causes scrol-
       ling.

  -[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 more. If
       the number n is negative, it indicates n lines less than the current
       screen size.  For example, if the screen is 24 lines, -z-4 sets the
       scrolling window to 20 lines.  If the screen is resized to 40 lines,
       the scrolling window automatically changes to 36 lines.

  +    If a command line option begins with +, the remainder of that option
       is taken to be an initial command to less. For example, +G tells less
       to start at the end of the file rather than the beginning, and +/xyz
       tells it to start at the first occurrence of "xyz" in the file.	As a
       special case, + acts like +g; that is, it starts the
       display at the specified line number (however, see the caveat under
       the "g" command above).	If the option starts with ++, the initial
       command applies to every file being viewed, not just the first one.
       The + command described previously may also be used to set (or change)
       an initial command for every file.


LINE EDITING
  When entering command line at the bottom of the screen (for example, a
  filename for the :e command, or the pattern for a search command), certain
  keys can be used to manipulate the command line.  Most commands have an
  alternate form in [ brackets ] which can be used if a key does not exist on
  a particular keyboard. (The bracketed forms do not work in the MS-DOS ver-
  sion.) Any of these special keys may be entered literally by preceding it
  with a backslash.  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 cancel 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 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 com-
       mand line (if they fit).

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


KEY BINDINGS
  You may define your own less commands by using the program lesskey (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.  See the less-
  key manual page for more details.


INPUT PREPROCESSOR
  You may define an "input preprocessor" for less. Before less opens a file,
  it first gives your input preprocessor a chance to modify the way the con-
  tents of the file are displayed.  An input preprocessor is simply an exe-
  cutable 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 origi-
  nal file.  However, it will appear to the user as if the original file is
  opened; that is, less will display the original filename as the name of the
  current file.

  An input preprocessor receives one command line argument, the original
  filename, as entered by the user.  It should create the replacement file,
  and when finished, print the name of the replacement file to its standard
  output.  If the input preprocessor does not output a replacement filename,
  less uses the original file, as normal.  To set up an input preprocessor,
  set the LESSOPEN environment variable to a command line which will invoke
  your input preprocessor.  This command line should include one occurence of
  the string "%s", which will be replaced by the filename when the input
  preprocessor command is invoked.

  When less closes a file opened in such a way, it will call another program,
  called the input postprocessor, which may perform any desired clean-up
  action (such as deleting the replacement file created by LESSOPEN).  This
  program receives two command line arguments, the original filename as
  entered by the user, and the name of the replacement file.  To set up an
  input postprocessor, set the LESSCLOSE environment variable to a command
  line which will invoke your input postprocessor.  It may include two
  occurences of the string "%s"; the first is replaced with the original name
  of the file and the second with the name of the replacement file, which was
  output by LESSOPEN.


  For example, on many Unix systems, these two scripts will allow you to keep
  files in compressed format, but still let less view them directly (by giv-
  ing less 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 executed and set
  LESSOPEN="lessopen.sh %s", and LESSCLOSE="lessclose.sh %s %s".  More com-
  plex LESSOPEN and LESSCLOSE scripts may be written to also accept the
  filename either with or without the .Z suffix, or to accept other types of
  compressed files, and so on.


NATIONAL CHARACTER SETS
  There are three types of characters in the input file:

  normal characters
       can be displayed directly to the screen.

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

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

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

  dos  Selects a character set appropriate for MS-DOS.

  In special cases, it may be desired to tailor less to use a character set
  other than the ones definable by LESSCHARSET.	 In this case, the environ-
  ment variable LESSCHARDEF can be used to define a character set.  It should
  be set to a string where each character in the string represents one char-
  acter in the character set.  The character "." is used for a normal charac-
  ter, "c" for control, and "b" for binary.  A decimal number may be used for
  repetition.  For example, "bccc4b." would mean character 0 is binary, 1, 2
  and 3 are control, 4, 5, 6 and 7 are binary, and 8 is normal.	 All charac-
  ters after the last are taken to be the same as the last, so characters 9
  through 255 would be normal.	(This is an example, and does not necessarily
  represent any real character set.)


  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
  setlocale interface, less 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 variable.  LESSBINFMT may begin with a "*" and one
  character to select the display attribute: "*k" is blinking, "*d" is bold,
  "*u" is underlined, "*s" is standout.	 If LESSBINFMT does not begin with a
  "*", normal attribute is assumed.  The remainder of LESSBINFMT is a string
  which may include one printf-style escape sequence (a % followed by x, X,
  o, d, etc.).	For example, if LESSBINFMT is "*u[%x]", binary characters are
  displayed in underlined hexadecimal surrounded by brackets.  The default if
  no LESSBINFMT is specified is "*d<%X>".


PROMPTS
  The -P option allows you to tailor the prompt to your preference.  The
  string given to the -P option replaces the specified prompt string.  Cer-
  tain characters in the string are interpreted specially.  The prompt
  mechanism is rather complicated to provide flexibility, but the ordinary
  user need not understand the details of constructing personalized prompt
  strings.

  A percent sign followed by a single character is expanded according to what
  the following character is:

  %bX  Replaced by the byte offset into the current input file.	 The b is
       followed by a single character (shown as X above) which specifies the
       line whose byte offset is to be used.  If the character is a "t", the
       byte offset of the top line in the display is used, an "m" means use
       the middle line, a "b" means use the bottom line, a "B" means use the
       line just after the bottom line, and a "j" means use the "target"
       line, as specified by the -j option.

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

  %E   Replaced by the name of the editor (from the EDITOR environment vari-
       able).  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.

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

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

  %m   Replaced by the total number of input files.

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

  %s   Same as %B.

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

  %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 condi-
  tions.  A question mark followed by a single character acts like an "IF":
  depending on the following character, a condition is evaluated.  If the
  condition is true, any characters following the question mark and condition
  character, up to a period, are included in the prompt.  If the condition is
  false, such characters are not included.  A colon appearing between the
  question mark and the period can be used to establish an "ELSE": any char-
  acters between the colon and the period are included in the string if and
  only if the IF condition is false.  Condition characters (which follow a
  question mark) may be:

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

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

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

  ?e   True if at end-of-file.

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

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

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

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

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

  ?pX  True if the percent into the current input file of the specified line
       is known.

  ?s   Same as "?B".

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

  Any characters other than the special ones (question mark, colon, period,
  percent, and backslash) become literally part of the prompt.	Any of the
  special characters may be included in the prompt literally by preceding it
  with a backslash.

  Some examples:

  ?f%f:Standard input.

  This prompt prints the filename, if known; otherwise the string "Standard
  input".

  ?f%f .?ltLine %lt:?pt%pt\%:?btByte %bt:-...

  This prompt would print the filename, if known.  The filename is followed
  by the line number, if known, otherwise the percent if known, otherwise the
  byte offset if known.	 Otherwise, a dash is printed.	Notice how each ques-
  tion 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 trun-
  cated.  This is the default prompt.  For reference, here are the defaults
  for the other two prompts (-m and -M respectively).  Each is broken into
  two lines here for readability only.

  ?n?f%f .?m(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 command is invoked.  The LESSEDIT string is expanded in
  the same way as the prompt strings.  The default value for LESSEDIT is:

	  %E ?lm+%lm. %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 variable can be changed to modify this default.


ENVIRONMENT VARIABLES

  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 less 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-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 less is being run.


SEE ALSO
  lesskey(1)


WARNINGS
  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.

  There is no way (yet) to modify key bindings for the line editing commands.

  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 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 nevertheless be found correctly by the search.


COPYRIGHT
  Copyright (c) 1984,1985,1989,1994  Mark Nudelman