X-Git-Url: https://ncurses.scripts.mit.edu/?p=ncurses.git;a=blobdiff_plain;f=doc%2Fhtml%2Fman%2Ftabs.1.html;h=2db7090d94f908f2bffde627dc814066d8c83a5d;hp=ab5201a489a33d41f6da7cd55a4a38352cff513d;hb=fe43d506ce08d1deef9e9e5a6d5fd4f9c9c32e1d;hpb=6208c89f98f1cf9fe0980bd8e791846ce007a13d diff --git a/doc/html/man/tabs.1.html b/doc/html/man/tabs.1.html index ab5201a4..2db7090d 100644 --- a/doc/html/man/tabs.1.html +++ b/doc/html/man/tabs.1.html @@ -1,6 +1,6 @@ - + tabs 1 - +

tabs 1

-tabs(1)                                                         tabs(1)
+tabs(1)                     General Commands Manual                    tabs(1)
 
 
 
@@ -54,47 +54,59 @@

DESCRIPTION

-       The  tabs  program clears and sets tab-stops on the termi-
-       nal.  This uses the terminfo  clear_all_tabs  and  set_tab
-       capabilities.   If  either  is  absent,  tabs is unable to
-       clear/set tab-stops.  The terminal should be configured to
-       use hard tabs, e.g.,
+       The  tabs program clears and sets tab-stops on the terminal.  This uses
+       the terminfo clear_all_tabs and set_tab  capabilities.   If  either  is
+       absent,  tabs is unable to clear/set tab-stops.  The terminal should be
+       configured to use hard tabs, e.g.,
 
-              stty tab0
+           stty tab0
+
+       Like clear(1), tabs writes to the standard output.   You  can  redirect
+       the standard output to a file (which prevents tabs from actually chang-
+       ing the tabstops), and later cat the file to the screen,  setting  tab-
+       stops at that point.
+
+       These  are  hardware  tabs, which cannot be queried rapidly by applica-
+       tions running in the terminal, if at all.  Curses and other full-screen
+       applications  may  use  hardware tabs in optimizing their output to the
+       terminal.  If the hardware tabstops differ from the information in  the
+       terminal  database, the result is unpredictable.  Before running curses
+       programs, you should either reset tab-stops to the standard interval
+
+           tabs -8
+
+       or use the reset program, since the normal initialization sequences  do
+       not ensure that tab-stops are reset.

OPTIONS

General Options

        -Tname
-            Tell tabs which terminal type to use.  If this option
-            is not given, tabs will  use  the  $TERM  environment
-            variable.   If  that  is  not  set,  it  will use the
-            ansi+tabs entry.
+            Tell  tabs  which  terminal  type  to  use.  If this option is not
+            given, tabs will use the $TERM environment variable.  If  that  is
+            not set, it will use the ansi+tabs entry.
 
-       -d   The debugging option shows a ruler line, followed  by
-            two  data  lines.   The  first  data  line  shows the
-            expected tab-stops marked with asterisks.  The second
-            data  line  shows  the  actual tab-stops, marked with
-            asterisks.
+       -d   The  debugging  option  shows  a  ruler line, followed by two data
+            lines.  The first data line shows the  expected  tab-stops  marked
+            with  asterisks.  The second data line shows the actual tab-stops,
+            marked with asterisks.
 
-       -n   This option tells tabs to check the options  and  run
-            any  debugging option, but not to modify the terminal
-            settings.
+       -n   This option tells tabs to check the options and run any  debugging
+            option, but not to modify the terminal settings.
 
-       -V   reports the version of ncurses which was used in this
-            program, and exits.
+       -V   reports the version of ncurses which was used in this program, and
+            exits.
 
-       The  tabs  program  processes  a single list of tab stops.
-       The last option to be processed which defines  a  list  is
-       the one that determines the list to be processed.
+       The tabs program processes a single list of tab stops.  The last option
+       to  be  processed  which  defines a list is the one that determines the
+       list to be processed.

Implicit Lists

-       Use  a  single number as an option, e.g., "-5" to set tabs
-       at the given interval (in this case  1,  6,  11,  16,  21,
-       etc.).   Tabs  are  repeated up to the right margin of the
-       screen.
+       Use a single number as an option, e.g., "-5" to set tabs at  the  given
+       interval  (in  this case 1, 6, 11, 16, 21, etc.).  Tabs are repeated up
+       to the right margin of the screen.
 
        Use "-0" to clear all tabs.
 
@@ -102,17 +114,18 @@

Explicit Lists

-       An explicit list can be defined after  the  options  (this
-       does  not  use  a "-").  The values in the list must be in
-       increasing numeric order, and greater than zero.  They are
-       separated by a comma or a blank, for example,
+       An explicit list can be defined after the options (this does not use  a
+       "-").   The values in the list must be in increasing numeric order, and
+       greater than zero.  They are separated by a comma or a blank, for exam-
+       ple,
 
-              tabs 1,6,11,16,21
-              tabs 1 6 11 16 21
-       Use  a  '+'  to treat a number as an increment relative to
-       the previous value, e.g.,
+           tabs 1,6,11,16,21
+           tabs 1 6 11 16 21
 
-              tabs 1,+5,+5,+5,+5
+       Use  a  "+"  to treat a number as an increment relative to the previous
+       value, e.g.,
+
+           tabs 1,+5,+5,+5,+5
 
        which is equivalent to the 1,6,11,16,21 example.
 
@@ -140,29 +153,63 @@

PORTABILITY

-       X/Open describes a +m option, to set  a  terminal's  left-
-       margin.   Very few of the entries in the terminal database
-       provide this capability.
+       IEEE  Std  1003.1/The  Open   Group   Base   Specifications   Issue   7
+       (POSIX.1-2008) describes a tabs utility.  However
+
+       o   This  standard describes a +m option, to set a terminal's left-mar-
+           gin.  Very few of the entries in the terminal database provide  the
+           smgl  (set_left_margin)  or smglp (set_left_margin_parm) capability
+           needed to support the feature.
+
+       o   There is no counterpart in X/Open Curses Issue 7 for this  utility,
+           unlike tput(1).
+
+       The  -d  (debug)  and -n (no-op) options are extensions not provided by
+       other implementations.
+
+       A tabs utility appeared in PWB/Unix 1.0 (1977).  There  was  a  reduced
+       version  of  the  tabs  utility in Unix 7th edition and in 3BSD (1979).
+       The latter supported a single "-n" option (to cause the first tab  stop
+       to be set on the left margin).  That option is not documented by POSIX.
+
+       The  PWB/Unix  tabs  utility,  which was included in System III (1980),
+       used built-in tables rather than the terminal database,  to  support  a
+       half-dozen  terminal  types.  It also had built-in logic to support the
+       left-margin, as well as a feature for copying the tab settings  from  a
+       file.
+
+       Later  versions  of  Unix,  e.g.,  SVr4, added support for the terminal
+       database, but kept the tables, as a fallback.  In an  earlier  develop-
+       ment  effort,  the  tab-stop initialization provided by tset (1982) and
+       incorporated into tput uses the terminal database,
+
+       POSIX documents no limits on the number of  tab  stops.   Documentation
+       for other implementations states that there is a limit on the number of
+       tab stops (e.g., 20 in PWB/Unix's tabs utility).  While some  terminals
+       may  not  accept  an arbitrary number of tab stops, this implementation
+       will attempt to set tab stops up to the right margin of the screen,  if
+       the given list happens to be that long.
+
+       The  Rationale section of the POSIX documentation goes into some detail
+       about the ways the committee considered redesigning the tabs  and  tput
+       utilities, without proposing an improved solution.  It comments that
 
-       The -d (debug) and -n (no-op) options are  extensions  not
-       provided by other implementations.
+            no  known  historical  version  of tabs supports the capability of
+            setting arbitrary tab stops.
 
-       Documentation  for other implementations states that there
-       is a limit on the number of tab stops.  While some  termi-
-       nals may not accept an arbitrary number of tab stops, this
-       implementation will attempt to set tab  stops  up  to  the
-       right  margin  of the screen, if the given list happens to
-       be that long.
+       However, the Explicit Lists described in this manual page  were  imple-
+       mented  in  PWB/Unix.  Those provide the capability of setting abitrary
+       tab stops.