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col - A semi-forgotten tool to converting man pages to text

The col utility reads from the standard input and writes to the standard output. It performs the line overlays implied by reverse line-feeds, and by forward and reverse half- line-feeds. It accepts several options

col [ -bfpx ]

Unless  option -x is used, all blank characters in the input will be converted to tab characters wherever possible. col is useful for filtering multi-column output made with the .rt command of nroff(1) and output resulting from use of the tbl(1) preprocessor but who uses those nowadays ?

The classic usage of col became converting man pages to text files:

 man wgateway | col -bx | mailx myself@mydomain

The ASCII control characters SO and SI are assumed by col to start and end text in an alternative character set. The character set to which each input character belongs is remembered, and on output SI and SO characters are generated as appropriate to ensure that each character is written in the correct character set.

On input, the only control characters accepted are space, backspace, tab, carriage-return and newline characters, SI, SO, VT, reverse line-feed, forward half-line-feed and reverse half-line-feed. The VT character is an alternative form of full reverse line-feed, included for compatibility with some earlier programs of this type. The only other characters to be copied to the output are those that are printable.

The ASCII codes for the control functions and line-motion sequences mentioned above are as given in the table below. ESC stands for the ASCII escape character, with the octal code 033; ESC- means a sequence of two characters, ESC followed by the character x.

     reverse line-feed             ESC-7
     reverse half-line-feed        ESC-8
     forward half-line-feed        ESC-9
     vertical-tab (VT)             013
     start-of-text (SO)            016
     end-of-text (SI)              017

OPTIONS

• -b Assume that the output device in use is not capable of backspacing. In this case, if two or more characters are to appear in the same place, only the last one read will be output.
   
• -f Although col accepts half-line motions in its input, it normally does not emit them on output. Instead, text that would appear between lines is moved to the next lower full-line boundary. This treatment can be suppressed by the -f (fine) option; in this case, the output from col may contain forward half-line-feeds (ESC-9), but will still never contain either kind of reverse line motion.
   
• -p Normally, col will ignore any escape sequences unknown to it that are found in its input; the -p option may be used to cause col to output these sequences as regular characters, subject to overprinting from reverse line motions. The use of this option is highly discouraged unless the user is fully aware of the textual position of the escape sequences.
   
• -x Prevents col from converting blank characters to tab characters on output wherever possible. Tab stops are considered to be at each column position n such that n modulo 8 equals 1.

ENVIRONMENT VARIABLES

EXIT STATUS

     0     Successful completion.

     >0    An error occurred.

ATTRIBUTES

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Availability                | SUNWesu                     |
    |_____________________________|_____________________________|
    | CSI                         | enabled                     |
    |_____________________________|_____________________________|

Example

#!/bin/ksh
#
# Solaris Man Page Save Script
# Purpose: Save man pages to ascii files
# Usage: Set variables and execute
# Dependencies: Data file containing command names
# (Solaris 8 commands included below)
# Outputs: Files named by the commands
#
## Submitter Email: gideon@infostruct.net
#*******************************************************

PATH=/usr/bin:/usr/sbin:/usr/ucb:/bin
MANPATH=/usr/share/man:/opt/SUNWvxvm/man:/opt/SUNWvxva/man

OUTPUTDIR=./manpgs

while read -r CMND
do

man $CMND | col -bx > $OUTPUTDIR/$CMND.txt

done < ./manpages.dat

exit 0


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### Sun Microsystems, Inc. is not responsible for the
### contents or the code enclosed. 
###
###
### Copyright 2007 Sun Microsystems, Inc. ALL RIGHTS RESERVED
### Use of this software is authorized pursuant to the
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##############################################################################

NOTES

col cannot back up more than 128 lines or handle more than 800 characters per line.

Local vertical motions that would result in backing up over the first line of the document are ignored. As a result, the first line must not have any superscripts.

Last modified: February 28, 2008