col(1) col(1)
NAME
col - filter reverse line feeds
SYNOPSIS
col [option ...]
DESCRIPTION
col reads from the standard input and writes the result to standard
output. It performs the line overlays implied by reverse line feeds
and forward or reverse half-line feeds.
col accepts half-line motions as input, but does not normally transfer
them to standard output. Instead, text that would appear between lines
is moved to before or after the next lower full-line boundary. Reverse
line feeds starting from the first line of a file are ignored.
On output, col substitutes tabs for blanks (octal 040), provided the
position of the following non-blank character is not affected. This
shortens printing time. The default spacing between tab stops is 8
characters. The ASCII control characters SO and SI [see ascii(5)] are
assumed by col to start and end text in an alternate 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 printed in the correct character set.
col is particularly useful for filtering multicolumn output produced
by the .rt command in nroff(1M) and output resulting from use of the
tbl(1M) preprocessor. The input format accepted by col matches the
output produced by nroff with either the -T37 or -Tlp options. You
should use -T37 (and the -f option of col) if the ultimate destination
of the output of col is a device that can interpret half-line feeds,
and -Tlp otherwise.
col ignores local vertical motions that would result in backing up
over the first line of the document. Thus the first line must not have
any superscripts.
col cannot back up more than 128 lines.
Non-printing and non-ASCII characters in the input are ignored, with
the following exceptions:
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col(1) col(1)
______________________________________________________________________
| Non-printing characters | ASCII value | |
| interpreted by col | (octal) | entered as |
|_________________________|______________|____________________________|
| Space (SP) | 040 | space bar |
|_________________________|______________|____________________________|
| Backspace (BS) | 010 | BACKSPACE |
|_________________________|______________|____________________________|
| Horizontal Tab (HT) | 011 | TAB |
|_________________________|______________|____________________________|
| Carriage Return (CR) | 015 | CTRL-M or appropriate key |
|_________________________|______________|____________________________|
| Line Feed (LF) | 012 | CTRL-J or appropriate key |
|_________________________|______________|____________________________|
| Shift In (SI) | 017 | CTRL-O |
|_________________________|______________|____________________________|
| Shift Out (SO) | 016 | CTRL-N |
|_________________________|______________|____________________________|
| Vertical Tab (VT) | 013 | CTRL-K |
|_________________________|______________|____________________________|
| Reverse line feed | 033 067 | ESC 7 |
|_________________________|______________|____________________________|
| Reverse half-line feed | 033 070 | ESC 8 |
|_________________________|______________|____________________________|
| Forward half-line feed | 033 071 | ESC 9 |
|_________________________|______________|____________________________|
The CTRL key and the second key have to be pressed simultaneously; the
ESC key (033) and the second key have to be pressed consecutively.
Unless the -p option is set, col normally removes any escape sequences
found in its input that are unknown to it.
OPTIONS
-b col assumes that the output device in use is not capable of back-
spacing. In this case, if two or more characters are to appear in
the same place, only the last one read will be output.
-f col outputs forward half-line feeds, but does not output either
kind of reverse line motion (half-line or full-line).
-p col will also accept escape sequences other than the ones
described above. Use -p only if you are fully aware of the conse-
quences!
-x col does not convert white space in input to tabs on output.
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col(1) col(1)
ERROR MESSAGES
col: bad option
You have specified an invalid option.
LOCALE
The LCMESSAGES environment variable governs the language in which
message texts are displayed. If LCMESSAGES is undefined or is defined
as the null string, it defaults to the value of LANG. If LANG is like-
wise undefined or null, the system acts as if it were not internation-
alized.
The LCALL environment variable governs the entire locale. LCALL
takes precedence over all the other environment variables which affect
internationalization.
EXAMPLES
The file texts contains the following characters:
text1 ESC 9text2 ESC 9text3 ESC 9text4 ESC 8 ESC 8text5
The following screen output is generated by col:
$ cat texts | col
text1
text2text3 text5
text4
The contents of a file containing these characters could also be out-
put in this way with normal forward processing.
SEE ALSO
nroff(1M), tbl(1M), ascii(5), meta-ascii(5).
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