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- LESS(1) Unix Programmer's Manual LESS(1)
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-
- NNNAAAMMMEEE
- less - opposite of more
-
- SSSYYYNNNOOOPPPSSSIIISSS
- llleeessssss ---???
- llleeessssss [[[-[[[+++]]]aaaBBBcccCCCdddeeeEEEfffHHHiiimmmMMMnnnNNNqqqQQQrrrsssSSSuuuUUUwww]]]
- [[[-bbb _b_u_f_s]]] [[[-hhh _l_i_n_e_s]]] [[[-jjj _l_i_n_e]]] [[[-kkk _k_e_y_f_i_l_e]]]
- [[[-{{{oooOOO}}} _l_o_g_f_i_l_e]]] [[[-ppp _p_a_t_t_e_r_n]]] [[[-PPP _p_r_o_m_p_t]]] [[[-ttt _t_a_g]]]
- [[[-TTT _t_a_g_f_i_l_e]]] [[[-xxx _t_a_b]]] [[[-yyy _l_i_n_e_s]]] [[[-[[[zzz]]] _l_i_n_e_s]]]
- [[[+++[[[+++]]]_c_m_d]]] [[[_f_i_l_e_n_a_m_e]]].........
-
-
- DDDEEESSSCCCRRRIIIPPPTTTIIIOOONNN
- _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 an up-
- arrow.)
-
- 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.
-
-
- CCCOOOMMMMMMAAANNNDDDSSS
- 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.
-
-
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- 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.)
-
- 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
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- bracket on the line.
-
- } If a right curly bracket appears in the bottom line
- displayed on the screen, the } command will go to the
- matching left curly bracket. The matching left curly
- bracket is positioned on the top line of the screen.
- If there is more than one right curly bracket on the
- top line, a number N may be used to specify the N-th
- bracket on the line.
-
- ( Like {, but applies to parentheses rather than curly
- brackets.
-
- ) Like }, but applies to parentheses rather than curly
- brackets.
-
- [ Like {, but applies to square brackets rather than
- curly brackets.
-
- ] Like }, but applies to square brackets rather than
- curly brackets.
-
- ESC-^F
- Followed by two characters, acts like {, but uses the
- two characters as open and close brackets,
- respectively. For example, "ESC ^F < >" could be used
- to go forward to the > which matches the < in the top
- displayed line.
-
- ESC-^B
- Followed by two characters, acts like }, but uses the
- two characters as open and close brackets,
- respectively. For example, "ESC ^B < >" could be used
- to go backward to the < which matches the > in the
- bottom displayed line.
-
- m Followed by any lowercase 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 containing
- 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).
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- 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 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 *.
-
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- ESC-N
- Repeat previous search, but in the reverse direction
- and crossing file boundaries.
-
- :e [filename]
- Examine a new file. If the filename is missing, the
- "current" file (see the :n and :p commands below) from
- the list of files in the command line is re-examined.
- A percent sign (%) in the filename is replaced by the
- name of the current file. A pound sign (#) is replaced
- by the name of the previously examined file. 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 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 message 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.
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- -- 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 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 or ESC ESC
- 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.
-
- ! 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.
-
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- OOOPPPTTTIIIOOONNNSSS
- 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 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 _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 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.
-
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- -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).
-
- -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 refuse to open non-
- regular files.
-
- -h_n Specifies a maximum number of lines to scroll backward.
- If it is necessary to scroll backward more than _n
- lines, the screen is repainted in a forward direction
- instead. (If the terminal does not have the ability to
- scroll backward, -h0 is implied.)
-
- -i Causes searches to ignore case; that is, uppercase and
- lowercase are considered identical. Also, text which
- is overstruck or underlined can be searched for. 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
- immediately after the target line. For example, if "-
- j4" is used, the target line is the fourth line on the
- screen, so searches begin at the fifth line on the
- screen.
-
- -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.
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- -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 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.
-
- -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
- special escape sequences. See the section on PROMPTS
- for more details.
-
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- -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,
- _l_e_s_s cannot keep track of the actual appearance of the
- screen (since this depends on how the screen responds
- to each type of control character). Thus, various
- display problems may result, such as long lines being
- split in the wrong place.
-
- -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
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- characters are treated specially: the overstruck text
- is printed using the terminal's hardware boldface
- capability. Other backspaces are deleted, along with
- the preceding character. Carriage returns immediately
- followed by a newline are deleted. Other carriage
- returns are handled as specified by the -r option.
-
- -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.
-
- -y_n Specifies a maximum number of lines to scroll forward.
- If it is necessary to scroll forward more than _n lines,
- the screen is repainted instead. The -c or -C option
- may be used to repaint from the top of the screen if
- desired. By default, any forward movement causes
- scrolling.
-
- -[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, as in "-_n" for compatibility with _m_o_r_e.
-
- + If a command line option begins with +++, the remainder
- of that option is taken to be an initial command 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 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.
-
-
- KKKEEEYYY BBBIIINNNDDDIIINNNGGGSSS
- 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. See the _l_e_s_s_k_e_y manual
- page for more details.
-
-
- NNNAAATTTIIIOOONNNAAALLL CCCHHHAAARRRAAACCCTTTEEERRR SSSEEETTTSSS
- There are three types of characters in the input file:
-
- normal characters
- can be displayed directly to the screen.
-
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- control characters
- should not be displayed directly, but are expected to
- be found in ordinary text files (such as backspace and
- tab).
-
- binary characters
- cannot be displayed directly and are not expected to be
- found in text files.
-
- By default, _l_e_s_s uses the ASCII character set. In the ASCII
- character set, characters with values between 128 and 255
- are treated as binary. The LESSCHARSET environment variable
- may be used to select another character set. If it is set
- to the value "latin1", the ISO 8859/1 character set is
- assumed. Latin-1 is the same as ASCII, except characters
- between 128 and 255 are treated as normal characters. The
- only valid values for LESSCHARSET currently are "ascii" and
- "latin1".
-
- In special cases, it may be desired to tailor _l_e_s_s to use a
- character set other than the ones definable by LESSCHARSET.
- In this case, the environment variable LESSCHARDEF can be
- used to define a character set. It should be set to a
- string where each character in the string represents one
- character in the character set. The character "." is used
- for a normal character, "c" for control, and "b" for binary.
- A decimal number may be used for repetition. For example,
- "bccc4b." would mean character 0 is binary, 1, 2 and 3 are
- control, 4, 5, 6 and 7 are binary, and 8 is normal. All
- characters after the last are taken to be the same as the
- last, so characters 9 through 255 would be normal. (This is
- an example, and does not necessarily represent any real
- character set.)
-
- 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".
-
- Control and binary characters are displayed in blinking
- mode. 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 an
- octal number preceded by a backslash. This octal format can
- be changed by setting the LESSBINFMT environment variable to
- a printf-style format string; the default is '\%o'. The
- blinking mode display of control and binary characters can
- be changed or disabled by preceding the LESSBINFMT format
- string with a "*" and one character to select the mode:
- "*k" is blinking, "*d" is bold, "*u" is underlined, and "*n"
- is normal (no special display attribute). For example, if
- LESSBINFMT is "*u[%x]", binary characters are displayed in
- underlined hexadecimal surrounded by brackets.
-
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-
-
- PPPRRROOOMMMPPPTTTSSS
- The -P option allows you to tailor the prompt to your
- preference. The string given to the -P option replaces the
- specified prompt string. Certain characters in the string
- are interpreted specially. The prompt mechanism is rather
- complicated to provide flexibility, but the ordinary user
- need not understand the details of constructing personalized
- prompt strings.
-
- A percent sign followed by a single character is expanded
- according to what the following character is:
-
- %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.
-
- %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.
-
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- If any item is unknown (for example, the file size if input
- is a pipe), a question mark is printed instead.
-
- The format of the prompt string can be changed depending on
- certain conditions. A question mark followed by a single
- character acts like an "IF": depending on the following
- character, a condition is evaluated. If the condition is
- true, any characters following the question mark and
- condition character, up to a period, are included in the
- prompt. If the condition is false, such characters are not
- included. A colon appearing between the question mark and
- the period can be used to establish an "ELSE": any
- characters between the colon and the period are included in
- the string if and only if the IF condition is false.
- Condition characters (which follow a question mark) may be:
-
- ?a True if any characters have been included in the prompt
- so far.
-
- ?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
- 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
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- string "Standard input".
-
- ?f%f .?ltLine %lt:?pt%pt\%:?btByte %bt:-...
-
- This prompt would print the filename, if known. The
- filename is followed by the line number, if known, otherwise
- the percent if known, otherwise the byte offset if known.
- Otherwise, a dash is printed. Notice how each question mark
- has a matching period, and how the % after the %pt is
- included literally by escaping it with a backslash.
-
- ?n?f%f\ .?m(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 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.
-
-
- EEENNNVVVIIIRRROOONNNMMMEEENNNTTT VVVAAARRRIIIAAABBBLLLEEESSS
-
-
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-
- COLUMNS
- Sets the number of columns on the screen. Takes
- precedence over the number of columns specified by the
- TERM variable.
-
- 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).
-
- 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.
-
- LESSEDIT
- Editor prototype string (used for the v command). See
- discussion under PROMPTS.
-
- LESSHELP
- Name of the help file.
-
- 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.
-
-
- SSSEEEEEE AAALLLSSSOOO
- lesskey(1)
-
-
- WWWAAARRRNNNIIINNNGGGSSS
- 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.
-
-
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-
- The handling of national character sets is nonstandard as
- well as insufficient for multibyte characters. It will
- probably change in a later release.
-
-
- The MS-DOS version also includes a -v option, which is used
- to force all output to be performed via the BIOS rather than
- by direct writes to the video memory. By default, the video
- memory is written directly if the screen is 80 columns wide
- and Desqview is not currently active.
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