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UNEXPAND

Section: User Commands (1)
Updated: February 2026
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unexpand - convert spaces to tabs

unexpand [,OPTION/]... [,FILE/]...

Convert blanks in each FILE to tabs, writing to standard output.

With no FILE, or when FILE is -, read standard input.

Mandatory arguments to long options are mandatory for short options too.

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#unexpan-a'-a, --allX'tty: link': convert all blanks, instead of just initial blanks
X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#unexpan-firs-only'--first-onlyX'tty: link': convert only leading sequences of blanks (overrides -a)
X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#unexpan-t'-t, --tabs=,NX'tty: link'/: have tabs N characters apart instead of 8 (enables -a)
X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#unexpan-t'-t, --tabs=,LISTX'tty: link'/: use comma separated list of tab positions. The last specified position can be prefixed with '/' to specify a tab size to use after the last explicitly specified tab stop. Also a prefix of '+' can be used to align remaining tab stops relative to the last specified tab stop instead of the first column
X'tty: link https://www.gnu.org/software/coreutils/unexpand#unexpan-help'--helpX'tty: link': display this help and exit
X'tty: link https://www.gnu.org/software/coreutils/unexpand#unexpan-version'--versionX'tty: link': output version information and exit

Written by David MacKenzie.