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Command: colrm | Section: 1 | Source: OpenBSD | File: colrm.1
COLRM(1) FreeBSD General Commands Manual COLRM(1)
NAME
colrm - remove columns from a file
SYNOPSIS
colrm [start [stop]]
DESCRIPTION
colrm removes selected columns from the lines of a file. Input is read
from the standard input. Output is written to the standard output.
If only the start column is specified, columns numbered less than the
start column will be written. If both start and stop columns are
specified, columns numbered less than the start column or greater than
the stop column will be written. Column numbering starts with one, not
zero.
Each character occupies the number of columns defined by wcwidth(3).
Zero-width characters belong to the previous column rather than to the
following column. If deletion of half of a double-width character is
requested, its remaining half is replaced by a blank character. Non-
printable characters are treated as if they had width 1. Each invalid
byte is regarded as a non-printable character.
Tab characters increment the input column count to the next multiple of
eight. If they intersect or follow a deletion, they are expanded to
blank characters such that the original alignment is preserved.
Backspace characters decrement the column count by the width of the
previous character. If they follow a character that is completely or
partially deleted, they are deleted together with that character. If
they follow a character that is partially deleted, they also suppress
printing of the replacement blank character.
For compatibility with IEEE Std 1003.1-2008 ("POSIX.1") fold(1), if a
double-width character is followed by two backspace characters instead of
the usual one, both are regarded as belonging to that character, and the
second one does not decrement the column count.
ENVIRONMENT
LC_CTYPE The character encoding locale(1). It decides which byte
sequences form characters and what their display width is. If
unset or set to "C", "POSIX", or an unsupported value, each
byte except tab and backspace is treated as a character of
display width 1.
SEE ALSO
awk(1), column(1), cut(1), paste(1)
HISTORY
The colrm utility first appeared in 1BSD.
AUTHORS
Jeff Schriebman wrote the original version of colrm in November 1974.
BUGS
If two characters of different widths are followed by two backspace
characters in a row, the column count is decremented twice by the width
of the second character rather than by the sum of both widths. This is
hardly a practical problem because not even backspace encoding in roff(7)
style uses such double-backspace sequences.
FreeBSD 14.1-RELEASE-p8 October 24, 2016 FreeBSD 14.1-RELEASE-p8