tr(1) General Commands Manual tr(1)
tr - translate characters
copies the standard input to the standard output with substitution or deletion of selected characters. Input characters from string1 are
replaced with the corresponding characters in string2. If necessary, string1 and string2 can be quoted to avoid pattern matching by the
recognizes the following command line options:
Translates on a byte-by-byte basis. When this flag is specified
does not support extended characters.
Complements the set of characters in
string1, which is the set of all characters in the current character set, as defined by the current setting of except
for those actually specified in the string1 argument. These characters are placed in the array in ascending collation
sequence, as defined by the current setting of
Deletes all occurrences of input characters or collating elements found in
the array specified in string1.
If and are both specified, all characters except those specified by string1 are deleted. The contents of string2 are
ignored, unless is also specified. Note, however, that the same string cannot be used for both the and the flags;
when both flags are specified, both string1 (used for deletion) and string2 (used for squeezing) are required.
If is not specified, each input character or collating element found in the array specified by string1 is replaced by
the character or collating element in the same relative position specified by string2.
Replaces any character specified in
string1 that occurs as a string of two or more repeating characters as a single instance of the character in string2.
If the string2 contains a character class, the argument's array contains all of the characters in that character
class. For example:
In a case conversion, however, the string2 array contains only those characters defined as the second characters in
each of the or character pairs, as appropriate. For example:
The following abbreviation conventions can be used to introduce ranges of characters, repeated characters or single-character collating
elements into the strings:
Stands for the range of collating elements
c1 through c2, inclusive, as defined by the current setting of the locale category.
Stands for all the characters belonging to the defined character class,
as defined by the current setting of locale category. The following character class names will be accepted when spec-
ified in string1: or Character classes are expanded in collation order.
When the and flags are specified together, any of the character class names are accepted in string2; otherwise, only
character class names or are accepted in string2 and then only if the corresponding character class and respectively)
is specified in the same relative position in string1. Such a specification is interpreted as a request for case
When appears in string1 and appears in string2, the arrays contain the characters from the mapping in the category of
the current locale. When appears in string1 and appears in string2, the arrays contain the characters from the map-
ping in the category of the current locale.
Stands for all the characters or collating elements belonging to the same
equivalence class as c, as defined by the current setting of locale category. An equivalence class expression is
allowed only in string1, or in string2 when it is being used by the combined and options.
Stands for n repetitions of a. If the first digit of n is n is considered octal; otherwise, n is treated as a decimal value. A
zero or missing n is interpreted as large enough to extend string2-based sequence to the length of the string1-based
The escape character can be used as in the shell to remove special meaning from any character in a string. In addition, followed by 1, 2,
or 3 octal digits represents the character whose ASCII code is given by those digits.
An ASCII NULL character in string1 or string2 can be represented only as an escaped character; i.e. as but is treated like other characters
and translated correctly if so specified. NULL characters in the input are not stripped out unless the option is given.
provides a default value for the internationalization variables that are unset or null. If is unset or null, the default value of "C" (see
lang(5)) is used. If any of the internationalization variables contains an invalid setting, will behave as if all internationalization
variables are set to "C". See environ(5).
If set to a non-empty string value, overrides the values of all the other internationalization variables.
determines the interpretation of text as single and/or multi-byte characters, the classification of characters as printable, and the char-
acters matched by character class expressions in regular expressions.
determines the locale that should be used to affect the format and contents of diagnostic messages written to standard error and informa-
tive messages written to standard output.
determines the location of message catalogues for the processing of
exits with one of the following values:
All input was processed successfully.
An error occurred.
For the ASCII character set and default collation sequence, create a list of all the words in file1, one per line in file2, where a word is
taken to be a maximal string of alphabetics. Quote the strings to protect the special characters from interpretation by the shell (012 is
the ASCII code for a new-line (line feed) character):
Same as above, but for all character sets and collation sequences:
Translate all lower case characters in file1 to upper case and write the result to standard output.
Use an equivalence class to identify accented variants of the base character in file1, strip them of diacritical marks and write the result
Translate each digit in file1 to a (number sign), and write the result to file2.
The (asterisk) tells to repeat the (number sign) enough times to make the second string as long as the first one.
was developed by OSF and HP.
ed(1), sh(1), ascii(5), environ(5), lang(5), regexp(5).