tr(1) User Commands tr(1)
NAME
tr - translate or delete characters
SYNOPSIS
tr [OPTION]... STRING1 [STRING2]
DESCRIPTION
Translate, squeeze, and/or delete characters from standard input,
writing to standard output. STRING1 and STRING2 specify arrays of
characters ARRAY1 and ARRAY2 that control the action.
-c, -C, --complement
use the complement of ARRAY1
-d, --delete
delete characters in ARRAY1, do not translate
-s, --squeeze-repeats
replace each sequence of a repeated character that is listed in
the last specified ARRAY, with a single occurrence of that
character
-t, --truncate-set1
first truncate ARRAY1 to length of ARRAY2
--help display this help and exit
--version
output version information and exit
ARRAYs are specified as strings of characters. Most represent
themselves. Interpreted sequences are:
\NNN character with octal value NNN (1 to 3 octal digits)
\\ backslash
\a audible BEL
\b backspace
\f form feed
\n new line
\r return
\t horizontal tab
\v vertical tab
CHAR1-CHAR2 all characters from CHAR1 to CHAR2 in ascending order
[CHAR*] in ARRAY2, copies of CHAR until length of ARRAY1
[CHAR*REPEAT] REPEAT copies of CHAR, REPEAT octal if starting with 0
[:alnum:] all letters and digits
[:alpha:] all letters
[:blank:] all horizontal whitespace
[:cntrl:] all control characters
[:digit:] all digits
[:graph:] all printable characters, not including space
[:lower:] all lower case letters
[:print:] all printable characters, including space
[:punct:] all punctuation characters
[:space:] all horizontal or vertical whitespace
[:upper:] all upper case letters
[:xdigit:] all hexadecimal digits
[=CHAR=] all characters which are equivalent to CHAR
Translation occurs if -d is not given and both STRING1 and STRING2
appear. -t is only significant when translating. ARRAY2 is extended
to length of ARRAY1 by repeating its last character as necessary.
Excess characters of ARRAY2 are ignored. Character classes expand in
unspecified order; while translating, '[:lower:]' and '[:upper:]' may
be used in pairs to specify case conversion. Squeezing occurs after
translation or deletion. Arguments like '[...]' should be quoted, to
avoid potential shell globbing.
BUGS
Full support is available only for safe single-byte locales, in which
every possible input byte represents a single character. The C locale
is safe in GNU systems, so you can avoid this issue in the shell by
running LC_ALL=C tr instead of plain tr.
AUTHOR
Written by Jim Meyering.
REPORTING BUGS
Report bugs to: <bug-coreutils@gnu.org>.
Report any translation bugs to: <https://translationproject.org/team/>.
GNU coreutils home page: <https://www.gnu.org/software/coreutils/>
General help using GNU software: <https://www.gnu.org/gethelp/>
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
Full documentation <https://www.gnu.org/software/coreutils/tr>
or available locally via: info '(coreutils) tr invocation'
GNU coreutils 9.12 September 2026 tr(1)
coreutils 9.12 - Generated Wed Sep 23 13:44:15 CDT 2026