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LLLLEEEESSSSSSSS((((1111)))) UUUUNNNNIIIIXXXX 5555....0000 LLLLEEEESSSSSSSS((((1111))))
NNNNAAAAMMMMEEEE
less - opposite of more
SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS
lllleeeessssssss [[[[----[[[[++++]]]]aaaaAAAABBBBccccCCCCddddeeeeEEEEiiiimmmmMMMMnnnnqqqqQQQQuuuuUUUUsssswwww]]]] [[[[----bbbb_N]]]] [[[[----hhhh_N]]]] [[[[----xxxx_N]]]] [[[[----[[[[zzzz]]]]_N]]]]
[[[[----PPPP[[[[mmmmMMMM====]]]]_s_t_r_i_n_g]]]] [[[[----[[[[llllLLLL]]]]_l_o_g_f_i_l_e]]]] [[[[++++_c_m_d]]]]
[[[[----tttt_t_a_g]]]] [[[[_f_i_l_e_n_a_m_e]]]]............
DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
_L_e_s_s is a program similar to _m_o_r_e (1), but which allows
backwards 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
preceeded by a decimal number, called N in the descriptions
below. The number is used by some commands, as indicated.
CCCCOOOOMMMMMMMMAAAANNNNDDDDSSSS
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 Help: display a summary of these commands. If you
forget all the other commands, remember this one.
SPACE or f or ^F or ^V
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.
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.
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.
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
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character.
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.
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.
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.)
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 postion at which the last "large"
movement command was executed. All marks are lost when
a new file is examined.
^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
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starts at the second line displayed (but see the -a
option, which changes this).
?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.
/!pattern
Like /, but the search is for the N-th line which does
NOT contain the pattern.
?!pattern
Like ?, but the search is for the N-th line which does
NOT contain the pattern.
n Repeat previous search, for N-th line containing the
last pattern (or NOT containing the last pattern, if
the previous search was /! or ?!).
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.
If the filename is a pound sign (#), the previously
examined file is re-examined.
^X^V or :e
Same as E. Warning: some systems use ^V as a special
literalization character.
N or :n
Examine the next file (from the list of files given in
the command line). If a number N is specified (not to
be confused with the command N), the N-th next file is
examined.
P or :p
Examine the previous file. If a number N is specified,
the N-th previous file is examined.
= or ^G
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 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),
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or a string value (such as -P or -t), a new value may
be entered after the option letter.
_ (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 ZZ
Exits _l_e_s_s.
The following two 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".
! 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. "!!" 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".
OOOOPPPPTTTTIIIIOOOONNNNSSSS
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 "-+".
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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.
-a Normally, forward searches start just after the top
displayed line (that is, at the second displayed line).
Thus, forward searches include the currently displayed
screen. The -a option causes forward searches to start
just after the bottom line displayed, thus skipping the
currently displayed screen.
-A The -A option causes searches to start at the second
SCREEN line displayed, as opposed to the default which
is to start at the second REAL line displayed. For
example, suppose a long real line occupies the first
three screen lines. The default search will start at
the second real line (the fourth screen line), while
the -A option will cause the search to start at the
second screen line (in the midst of the first real
line). (This option is rarely useful.)
-b The -b_n option tells _l_e_s_s to use a non-standard number
of buffers. Buffers are 1K, and normally 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 Normally, when data is coming from standard input,
buffers are allocated automatically as needed, to avoid
loss of data. The -B option disables this feature, 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.
-c Normally, _l_e_s_s will repaint the screen by scrolling
from the bottom of the screen. If the -c option is
set, when _l_e_s_s needs to change the entire display, it
will paint from the top line down.
-C The -C option is like -c, but the screen is cleared
before it is repainted.
-d Normally, _l_e_s_s will complain if the terminal is dumb;
that is, lacks some important capability, such as the
ability to clear the screen or scroll backwards. The
-d option suppresses this complaint (but does not
otherwise change the behavior of the program on a dumb
terminal).
-e Normally the only way to exit less is via the "q"
command. The -e option tells less to automatically
exit the second time it reaches end-of-file.
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-E The -E flag causes less to exit the first time it
reaches end-of-file.
-h Normally, _l_e_s_s will scroll backwards when backwards
movement is necessary. The -h option specifies a
maximum number of lines to scroll backwards. If it is
necessary to move backwards more than this many lines,
the screen is repainted in a forward direction. (If
the terminal does not have the ability to scroll
backwards, -h0 is implied.)
-i The -i option causes searches to ignore case; that is,
uppercase and lowercase are considered identical.
Also, text which is overstruck or underlined can be
searched for.
-l The -l option, followed immediately by a filename, will
cause _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, less will ask for confirmation before
overwriting it.
-L The -L option is like -l, but it will overwrite an
existing file without asking for confirmation.
If no log file has been specified, the -l and -L
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.
-m Normally, _l_e_s_s prompts with a colon. The -m option
causes _l_e_s_s to prompt verbosely (like _m_o_r_e), with the
percent into the file.
-M The -M option causes _l_e_s_s to prompt even more verbosely
than _m_o_r_e.
-n The -n flag 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.
-P The -P option provides a way to tailor the three prompt
styles to your own preference. You would normally put
this option in your LESS environment variable, rather
than type it in with each less command. Such an option
must either be the last option in the LESS variable, or
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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.
-q Normally, if an attempt is made to scroll past the end
of the file or before the beginning of the file, the
terminal bell is rung to indicate this fact. The -q
option tells _l_e_s_s not to ring the bell at such times.
If the terminal has a "visual bell", it is used
instead.
-Q Even if -q is given, _l_e_s_s will ring the bell on certain
other errors, such as typing an invalid character. The
-Q option tells _l_e_s_s to be quiet all the time; that is,
never ring the terminal bell. If the terminal has a
"visual bell", it is used instead.
-s The -s option causes consecutive blank lines to be
squeezed into a single blank line. This is useful when
viewing _n_r_o_f_f output.
-t 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 less
(using the - command) as a way of examining a new file.
-u If the -u option is given, backspaces are treated as
printable characters; that is, they are sent to the
terminal when they appear in the input.
-U If the -U option is given, backspaces are printed as
the two character sequence "^H".
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 preceeding character.
-w Normally, _l_e_s_s uses a tilde character to represent
lines past the end of the file. The -w option causes
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blank lines to be used instead.
-x The -x_n option sets tab stops every _n positions. The
default for _n is 8.
-[z] When given a backwards or forwards window command, _l_e_s_s
will by default scroll backwards or forwards one
screenful of lines. The -z_n option changes the default
scrolling window size to _n lines. Note that the "z" is
optional 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 occurence 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.
KKKKEEEEYYYY BBBBIIIINNNNDDDDIIIINNNNGGGGSSSS
You may define your own less 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.
PPPPRRRROOOOMMMMPPPPTTTTSSSS
The -P option allows you to tailor the prompt to your
preference. The string given to the -P option replaces the
specified prompt string. Certain characters in the string
are interpreted specially. The prompt mechanism is rather
complicated to provide flexibility, but the ordinary user
need not understand the details of constructing personalized
prompt strings.
A percent sign followed by a single character is expanded
according to what the following character is:
%bX Replaced by the byte offset into the current input
file. The b is followed by a single character (shown
as X above) which specifies the line whose byte offset
is to be used. If the character is a "t", the byte
offset of the top line in the display is used, an "m"
means use the middle line, a "b" means use the bottom
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line, and a "B" means use the line just after the
bottom line.
%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.
%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 Replaced by the size of the current input file.
%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 conditions. A question mark followed by a single
character acts like an "IF": depending on the following
character, a condition is evaluated. If the condition is
true, any characters following the question mark and
condition character, up to a period, are included in the
prompt. If the condition is false, such characters are not
included. A colon appearing between the question mark and
the period can be used to establish an "ELSE": any
characters between the colon and the period are included in
the string if and only if the IF condition is false.
Condition characters (which follow a question mark) may be:
?a True if any characters have been included in the prompt
so far.
?bX True if the byte offset of the specified line is known.
?e True if at end-of-file.
?f True if there is an input filename (that is, if input
is not a pipe).
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?lX True if the line number of the specified line 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 True if the size of current input file is known.
?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 preceeding it with a
backslash.
Some examples:
?f%f:Standard input.
This prompt prints the filename, if known; otherwise the
string "Standard input".
?f%f .?ltLine %lt:?pt%pt:?btByte %bt:-...
This prompt would print the filename, if known. The
filename is followed by the line number, if known, otherwise
the percent if known, otherwise the byte offset if known.
Otherwise, a dash is printed. Notice how each question mark
has a matching period, and how the % after the %pt is
included literally by escaping it with a backslash.
?n?f%f .?m(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 :byte %bB?s/%s ..
Page 10 (printed 7/19/88)
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?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 .
byte %bB?s/%s. ?e(END) :?pB%pB\%..%t
SSSSEEEEEEEE AAAALLLLSSSSOOOO
lesskey(1)
WWWWAAAARRRRNNNNIIIINNNNGGGGSSSS
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.
Page 11 (printed 7/19/88)
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.