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TAC
Section: User Commands (1)Updated: February 2026
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NAME
tac - concatenate and print files in reverseSYNOPSIS
tac [,OPTION/]... [,FILE/]...DESCRIPTION
Write each FILE to standard output, last line first.
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#ta-b'-b, --beforeX'tty: link'
- attach the separator before instead of after
- X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#ta-r'-r, --regexX'tty: link'
- interpret the separator as a regular expression
- X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#ta-s'-s, --separator=,STRINGX'tty: link'/
- use STRING as the separator instead of newline
- X'tty: link https://www.gnu.org/software/coreutils/tac#ta-help'--helpX'tty: link'
- display this help and exit
- X'tty: link https://www.gnu.org/software/coreutils/tac#ta-version'--versionX'tty: link'
- output version information and exit
Non-seekable input is buffered to $TMPDIR, defaulting to ,/tmp/.
AUTHOR
Written by Jay Lepreau and David MacKenzie.REPORTING BUGS
Report bugs to: bug-coreutils@gnu.org
Report Gentoo bugs to: https://bugs.gentoo.org/
GNU coreutils home page: <https://www.gnu.org/software/coreutils/>
General help using GNU software: <https://www.gnu.org/gethelp/>
Report any translation bugs to <https://translationproject.org/team/>
SEE ALSO
cat(1), rev(1)
Full documentation <https://www.gnu.org/software/coreutils/tac>
or available locally via: info aq(coreutils) tac invocationaq
Packaged by Gentoo (9.10 (p0))
Copyright © 2026 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.