United Public Domain Gold 2/United Public Domain Gold 2.iso/music_utilities/pt030.dms/pt030.adf/Less/Less.doc

Text File | 1987-06-15 | 15KB | 463 lines

_l_e_s_s - _o_p_p_o_s_i_t_e _o_f _m_o_r_e

_l_e_s_s [-_d_s_t_w_c_C_e_E_m_M_q_Q_u_U] [-_h_N] [-b[fp]_N] [-x_N] [-[z]_N]
     [-_P[_m_M]_s_t_r_i_n_g] [-[lL]_l_o_g_f_i_l_e] [+_c_m_d]  [_f_i_l_e_n_a_m_e]...

_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 fas-
ter than text editors like _v_i (1).  _L_e_s_s uses termcap, 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 descrip-
tions below.  The number is used by some commands, as  indi-
cated.


_I_n _t_h_e _f_o_l_l_o_w_i_n_g _d_e_s_c_r_i_p_t_i_o_n_s, ^_X _m_e_a_n_s _c_o_n_t_r_o_l-_X.

H    Help: display a summary of these commands.  If you for-
     get all the other commands, remember this one.


SPACEScroll forward N lines, default one window (see  option
     -z below).  If N is more than the screen size, only the
     final screenful is displayed.


f or ^F
     Same as SPACE.


b or ^B
     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.


RETURNScroll forward N lines, default 1.  The entire N lines
     are displayed, even if N is more than the screen size.


e or ^E
     Same as RETURN.


j or ^J
     Also the same as RETURN.





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y or ^Y
     Scroll backward N lines, default 1.  The entire N lines
     are displayed, even if N is more than the screen size.

k or ^K
     Same as y.


d or ^D
     Scroll forward N lines, default 10.  If N is specified,
     it  becomes the new default for subsequent d and u com-
     mands.


u or ^U
     Scroll backward N lines, default 10.  If  N  is  speci-
     fied, 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    Go to line N in  the  file,  default  1  (beginning  of
     file).  (Warning: this may be slow if N is large.)


G    Go to line N in the file, default the end of the  file.
     (Warning:  this  may  be slow if standard input, rather
     than a file, is being read.)


p    Go to a position N percent into the file.  N should  be
     between 0 and 100.  (This is possible 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.)


%    Same as p.


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



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     with that letter.  Followed by  another  single  quote,
     returns  to the postion at which the last "large" move-
     ment command was executed.  All marks are lost  when  a
     new file is examined.


/pattern
     Search forward in the file for the N-th line containing
     the  pattern.  N defaults to 1.  The pattern is a regu-
     lar expression, as recognized by _e_d.  The search starts
     at  the  second  line displayed (but see the -t option,
     which changes this).


?pattern
     Search backward in the file for the N-th line  contain-
     ing the pattern.  The search starts at the line immedi-
     ately before the top line displayed.


n    Repeat previous search, for N-th  line  containing  the
     last pattern.


E    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.


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    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 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 toggle the setting of that option and
     print a message describing the new setting.





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                           - 4 -


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


V    Prints the version number of _l_e_s_s being run.


q    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 vari-
     able EDITOR, or defaults to "vi".


! shell-command
     Invokes a shell to run the shell-command given.  A per-
     cent sign in the command is replaced by the name of the
     current file.  "!!" repeats the last shell command.


_C_o_m_m_a_n_d _l_i_n_e _o_p_t_i_o_n_s _a_r_e _d_e_s_c_r_i_b_e_d _b_e_l_o_w.  _M_o_s_t _o_p_t_i_o_n_s  _m_a_y
_b_e _c_h_a_n_g_e_d _w_h_i_l_e _l_e_s_s is running, via the "-" command.

     Options are also taken from  the  environment  variable
"LESS".   For  example, if you like more-style prompting, to
avoid typing "less -m ..." each time _l_e_s_s  is  invoked,  you
might tell _c_s_h:

setenv LESS m

or if you use _s_h:

LESS=m; export LESS

The environment variable is parsed before the command  line,
so  command line options override the LESS environment vari-
able.  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.

-b   The -b_n option tells _l_e_s_s to use a non-standard  buffer
     size.   There  are two standard (default) buffer sizes,
     one is used when a file is being  read  and  the  other
     when  a  pipe  (standard  input)  is  being  read.  The
     current defaults are 5 buffers for  files  and  12  for
     pipes.   (Buffers  are 1024 bytes.) The number _n speci-
     fies a different number of buffers to use.  The -b  may
     be followed by "f", in which case only the file default



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     is changed, or by "p"  in  which  case  only  the  pipe
     default is changed.  Otherwise, both are changed.

-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 oth-
     erwise change the behavior of the  program  on  a  dumb
     terminal).

-e   Normally the only way to exit less is via the "q"  com-
     mand.   The  -e option tells less to automatically exit
     the second time it reaches end-of-file.

-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 max-
     imum 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 back-
     wards, -h0 is implied.)

-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 overwrit-
     ing it.

-L   The -L option is like -l,  but  it  will  overwrite  an
     existing file without asking for confirmation.

-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.

-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



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     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.   The
     string  consists  of  a  sequence  of letters which are
     replaced with certain predefined strings, as follows:
          Ffile name
          ffile name, only once
          Ofile n of n
          ofile n of n, only once
          bbyte offset
          ppercent into file
          Ppercent if known, else byte offset
     Angle brackets, < and >, may  be  used  to  surround  a
     literal  string  to  be  included  in  the prompt.  The
     defaults are "fo" for the short prompt, "foP"  for  the
     medium prompt, and "Fobp" for the long prompt.
     Example: Setting your LESS variable  to  "PmFOP$PMFObp"
     would  change  the  medium  and  long prompts to always
     include the file name and "file n of n" message.
     Another example: Setting your LESS variable to
     "mPm<--Less-->FoPe" would change the medium  prompt  to
     the  string  "--Less--"  followed  by the file name and
     percent into the file.   It  also  selects  the  medium
     prompt  as  the  default  prompt  (because of the first
     "m").

-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   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 -t option causes forward searches to start
     just after the bottom line displayed, thus skipping the
     currently displayed screen.

-u   If the -u option is given, backspaces  are  treated  as
     printable  characters;  that  is,  they are sent to the



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     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 spe-
     cially: the underlined  text  is  displayed  using  the
     terminal's   hardware  underlining  capability.   Also,
     backspaces which appear between two  identical  charac-
     ters  are  treated  specially:  the  overstruck text is
     printed using the terminal's hardware boldface capabil-
     ity.   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
     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.  If _n is greater than
     the screen size, the scrolling window size will be  set
     to  one  screenful.  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 previ-
     ously  may  also  be used to set (or change) an initial
     command for every file.


_W_h_e_n _u_s_e_d _o_n _s_t_a_n_d_a_r_d _i_n_p_u_t (_r_a_t_h_e_r _t_h_a_n _a  _f_i_l_e),  _y_o_u  _c_a_n
_m_o_v_e  _b_a_c_k_w_a_r_d_s  _o_n_l_y _a _f_i_n_i_t_e _a_m_o_u_n_t, _c_o_r_r_e_s_p_o_n_d_i_n_g _t_o _t_h_a_t
_p_o_r_t_i_o_n _o_f _t_h_e _f_i_l_e _w_h_i_c_h _i_s _s_t_i_l_l _b_u_f_f_e_r_e_d.  _T_h_e -_b  _o_p_t_i_o_n
_m_a_y _b_e _u_s_e_d _t_o _e_x_p_a_n_d _t_h_e _b_u_f_f_e_r _s_p_a_c_e.








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