NAME¶

tac - concatenate and print files in reverse

SYNOPSIS¶

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.

-b, --before

attach the separator before instead of after

-r, --regex

interpret the separator as a regular expression

-s, --separator=STRING

use STRING as the separator instead of newline

--help

display this help and exit

--version

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
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/>

COPYRIGHT¶

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.

SEE ALSO¶

cat(1), rev(1)

Full documentation <https://www.gnu.org/software/coreutils/tac>
or available locally via: info '(coreutils) tac invocation'