The following options are available:
Complement the set of characters in
|Delete characters in string1 from the input.
|Squeeze multiple occurrences of the characters listed in the last operand (either string1 or string2) in the input into a single instance of the character. This occurs after all deletion and translation is completed.
|Guarantee that any output is unbuffered.
In the first synopsis form, the characters in string1 are translated into the characters in string2 where the first character in string1 is translated into the first character in string2 and so on. If string1 is longer than string2, the last character found in string2 is duplicated until string1 is exhausted.
In the second synopsis form, the characters in string1 are deleted from the input.
In the third synopsis form, the characters in
are compressed as described for the
In the fourth synopsis form, the characters in
are deleted from the input, and the characters in
are compressed as described for the
The following conventions can be used in string1 and string2 to specify sets of characters:
|Any character not described by one of the following conventions represents itself.
|A backslash followed by 1, 2 or 3 octal digits represents a character with that encoded value. To follow an octal sequence with a digit as a character, left zero-pad the octal sequence to the full 3 octal digits.
A backslash followed by certain special characters maps to special
A backslash followed by any other character maps to that character.
For non-octal range endpoints
represents the range of characters between the range endpoints, inclusive,
in ascending order,
as defined by the collation sequence.
If either or both of the range endpoints are octal sequences, it
represents the range of specific coded values between the
range endpoints, inclusive.
See the COMPATIBILITY section below for an important note regarding differences in the way the current implementation interprets range expressions differently from previous implementations.
Represents all characters belonging to the defined character class.
Class names are:
When "[:lower:]" appears in string1 and "[:upper:]" appears in the same relative position in string2, it represents the characters pairs from the toupper mapping in the LC_CTYPE category of the current locale. When "[:upper:]" appears in string1 and "[:lower:]" appears in the same relative position in string2, it represents the characters pairs from the tolower mapping in the LC_CTYPE category of the current locale.
With the exception of case conversion, characters in the classes are in unspecified order.
For specific information as to which ASCII characters are included in these classes, see ctype(3) and related manual pages.
|Represents all characters belonging to the same equivalence class as equiv, ordered by their encoded values.
|Represents n repeated occurrences of the character represented by #. This expression is only valid when it occurs in string2. If n is omitted or is zero, it is be interpreted as large enough to extend string2 sequence to the length of string1. If n has a leading zero, it is interpreted as an octal value, otherwise, it is interpreted as a decimal value.
Create a list of the words in file1, one per line, where a word is taken to be a maximal string of letters.
Translate the contents of file1 to upper-case.
(This should be preferred over the traditional Unix idiom of "tr a-z A-Z", since it works correctly in all locales.)
Strip out non-printable characters from file1.
Remove diacritical marks from all accented variants of the letter ‘e’:
tr q[=e=]q qeq
"[=equiv=]" expression and collation for ranges are implemented for single byte locales only.
System V has historically implemented character ranges using the syntax "[c-c]" instead of the "c-c" used by historic BSD implementations and standardized by POSIX. System V shell scripts should work under this implementation as long as the range is intended to map in another range, i.e., the command "tr [a-z] [A-Z]" will work as it will map the ‘amp;[’ character in string1 to the ‘amp;[’ character in string2. However, if the shell script is deleting or squeezing characters as in the command "tr -d [a-z]", the characters ‘amp;[’ and ‘amp;]’ will be included in the deletion or compression list which would not have happened under a historic System V implementation. Additionally, any scripts that depended on the sequence "a-z" to represent the three characters ‘a’, ‘-’ and ‘z’ will have to be rewritten as "a\-z".
The tr utility has historically not permitted the manipulation of NUL bytes in its input and, additionally, stripped NUL's from its input stream. This implementation has removed this behavior as a bug.
utility has historically been extremely forgiving of syntax errors,
for example, the
It should be noted that the feature wherein the last character of
is duplicated if
has less characters than
is permitted by POSIX but is not required.
Shell scripts attempting to be portable to other POSIX systems should use
convention instead of relying on this behavior.
|October 13, 2006