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📛 NAME

col - filter reverse line feeds from input

🚀 Quick Reference

Use Case	Command	Description
Filter reverse line feeds	col	Reads stdin, outputs forward line feeds only
Remove backspaces	col -b	Output only last character per column
Output tabs instead of spaces	col -h	Replace multiple spaces with tabs
Output spaces instead of tabs	col -x	Keep spaces, no tab conversion
Allow half-forward line feeds	col -f	Print half-line characters on same line

📋 SYNOPSIS

col options

📝 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. It also replaces any whitespace 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.

⚙️ OPTIONS

🔙 -b, --no-backspaces

Do not output any backspaces, printing only the last character written to each column position.

🔀 -f, --fine

Permit half-forward line feeds. Normally characters destined for a half-line boundary are printed on the following line.

↹ -h, --tabs

Output tabs instead of multiple spaces.

📏 -l, --lines number

Buffer at least number lines in memory. By default, 128 lines are buffered.

🔓 -p, --pass

Force unknown control sequences to be passed through unchanged. Normally col will filter out any control sequences other than those recognized and interpreted by itself, which are listed below.

🔲 -x, --spaces

Output multiple spaces instead of tabs.

ℹ️ -V, --version

Display version information and exit.

❓ -H, --help

Display help text and exit.

✅ CONFORMING TO

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

📝 NOTES

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

• 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
• newline — forward line feed (10); also does carriage return
• carriage return — (13)
• 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.

📜 HISTORY

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

📚 SEE ALSO

expand(1), nroff(1), tbl(1)

🐛 REPORTING BUGS

For bug reports, use the issue tracker at https://github.com/karelzak/util-linux/issues.

📦 AVAILABILITY

The col command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.

📛 NAME 🚀 Quick Reference 📋 SYNOPSIS 📝 DESCRIPTION ⚙️ OPTIONS ✅ CONFORMING TO 📝 NOTES 📜 HISTORY 📚 SEE ALSO 🐛 REPORTING BUGS 📦 AVAILABILITY