col(1) — Commands
NAME
col − Filters text containing linefeeds
SYNOPSIS
col [-bfhpx] [-l number]
The col command reads from standard input and writes to standard output.
STANDARDS
Interfaces documented on this reference page conform to industry standards as follows:
col: XPG4, XPG4−UNIX
Refer to the standards(5) reference page for more information about industry standards and associated tags.
FLAGS
-bAssumes that the output device in use is not capable of backspacing. In this case, if two or more characters are to be displayed in the same position, only the last one that is read is displayed in the output. This function is useful for converting nroff output to produce readable results on terminals or printers that do not support underlining or overstriking characters.
-fSuppresses the default treatment of half-line motions in the input. Normally, col does not emit half-line motions on output, although it does accept them in its input. With this flag, output may contain forward half-linefeeds (<ESC-9>), but not reverse linefeeds (<ESC-7> or <ESC-8>).
-h[Digital] Compresses spaces into tabs. This is the default.
-l number
[Digital] Buffers at least number lines in memory. By default, 128 lines are buffered.
-pDisplays unknown escape sequences as characters, subject to overprinting from reverse line motions. Normally, col ignores them. You should be fully aware of the textual position of escape sequences before you use this flag.
-xOutputs multiple spaces instead of tabs.
PARAMETERS
None
DESCRIPTION
The col command performs the line overlays implied by reverse linefeeds (ASCII <ESC-7>), and by forward and reverse half-linefeeds (ASCII <ESC-9> and ASCII <ESC-8>). It also replaces white-space characters with tabs where possible.
[Digital] The col command is particularly useful for filtering multicolumn output made by the nroff and tbl commands.
The col command assumes that the ASCII control characters SO (\017) and SI (\016) begin and end text in an alternate character set. The col command remembers the character set each input character belongs to, and on output generates SI and SO characters as appropriate to ensure that each character is printed in the correct character set.
On input, the col command accepts only the control characters for the <Space>, <Backspace>, <Tab>, and <Return> keys; the newline character; the SI, SO, and VT control characters; and <ESC-7>, <ESC-8>, or <ESC-9>. The VT control character (\013) is an alternate form of full reverse linefeed included for compatibility with some earlier programs of this type. The col command discards all other nonprinting characters.
[Digital] If the input attempts to back up to the last flushed line, col displays a warning message.
ENVIRONMENT VARIABLES
The following environment variables affect the execution of col:
LANGProvides a default value for the internationalization variables that are unset or null. If LANG is unset or null, the corresponding value from the default locale is used. If any of the internationalization variables contain an invalid setting, the utility behaves as if none of the variables had been defined.
LC_ALLIf set to a non-empty string value, overrides the values of all the other internationalization variables.
LC_CTYPEDetermines the locale for the interpretation of sequences of bytes of text data as characters (for example, single-byte as opposed to multibyte characters in arguments).
LC_MESSAGESDetermines the locale for the format and contents of diagnostic messages written to standard error.
NLSPATHDetermines the location of message catalogues for the processing of LC_MESSAGES.
NOTES
1.Depending on the printer, using the -x flag may increase printing time.
2.Local vertical motion that causes a backwards move over the first line of input is ignored. The first line of input may not have any superscripts.
3.This command is marked for possible future withdrawal from the XPG4−UNIX standard. It may be replaced by features designed for greater internationalization features.
EXIT VALUES
The following exit values are returned:
0Successful completion
>0An error occurred