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col - Unix, Linux Command


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NAME

col - filter reverse line feeds from input

SYNOPSIS

col [-bfpx] [-l num]

DESCRIPTION

Col filters out reverse (and half reverse) line feeds so the output is in the correct order with only forward and half forward line feeds, and replaces white-space characters with tabs where possible. This can be useful in processing the output of nroff(1) and tbl(1).

Col reads from standard input and writes to standard output.

The options are as follows:

TagDescription
-b Do not output any backspaces, printing only the last character written to each column position.
-f Forward half line feeds are permitted (‘‘fine’’ mode). Normally characters printed on a half line boundary are printed on the following line.
-p Force unknown control sequences to be passed through unchanged. Normally, col will filter out any control sequences from the input other than those recognized and interpreted by itself, which are listed below.
-x Output multiple spaces instead of tabs.
-l num
  Buffer at least num lines in memory. By default, 128 lines are buffered.

The control sequences for carriage motion that col understands and their decimal values are listed in the following table:

TagDescription
ESC-7 reverse line feed (escape then 7)
ESC-8 half reverse line feed (escape then 8)
ESC-9 half forward line feed (escape then 9)
backspace moves back one column (8); ignored in the first column
carriage return
  (13)
newline forward line feed (10); also does carriage return
shift in shift to normal character set (15)
shift out shift to alternate character set (14)
space moves forward one column (32)
tab moves forward to next tab stop (9)
vertical tab reverse line feed (11)

All unrecognized control characters and escape sequences are discarded.

Col keeps track of the character set as characters are read and makes sure the character set is correct when they are output.

If the input attempts to back up to the last flushed line, col will display a warning message.

SEE ALSO

nroff(1), tbl(1)

STANDARDS

The col utility conforms to the Single UNIX Specification, Version 2. The -l option is an extension to the standard.

HISTORY

A col command appeared in Version 6 AT&T UNIX.

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