1. Technology
Linux / Unix Command: tr
Command Library

NAME

tr - translate or delete characters  

SYNOPSIS

tr [OPTION]... SET1 [SET2]  

DESCRIPTION

Translate, squeeze, and/or delete characters from standard input, writing to standard output.

-c, --complement
first complement SET1
-d, --delete
delete characters in SET1, do not translate
-s, --squeeze-repeats
replace each input sequence of a repeated character that is listed in SET1 with a single occurrence of that character
-t, --truncate-set1
first truncate SET1 to length of SET2
--help
display this help and exit
--version
output version information and exit

SETs 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 SET2, copies of CHAR until length of SET1
[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 SET1 and SET2 appear. -t may be used only when translating. SET2 is extended to length of SET1 by repeating its last character as necessary. Excess characters of SET2 are ignored. Only [:lower:] and [:upper:] are guaranteed to expand in ascending order; used in SET2 while translating, they may only be used in pairs to specify case conversion. -s uses SET1 if not translating nor deleting; else squeezing uses SET2 and occurs after translation or deletion.  

SEE ALSO

The full documentation for tr is maintained as a Texinfo manual. If the info and tr programs are properly installed at your site, the command
info tr

should give you access to the complete manual.


Important: Use the man command (% man) to see how a command is used on your particular computer.

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