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.\" @(#)tr.1 6.9 (Berkeley) 10/27/91
.Nd Translate Characters.
utility copies the standard input to the standard output with substitution
or deletion of selected characters.
The following options are available:
Complements the set of characters in
that is ``-c ab'' includes every character except for ``a'' and ``b''.
option causes characters to be deleted from the input.
option squeezes multiple occurrences of the characters listed in the last
in the input into a single instance of the character.
This occurs after all deletion and translation is completed.
In the first synopsis form, the characters in
are translated into the characters in
where the first character in
is translated into the first character in
the last character found in
In the second synopsis form, the characters in
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
to specify sets of characters:
.Bl -tag -width [:equiv:]
Any character not described by one of the following conventions
A backslash followed by 1, 2 or 3 octal digits represents a character
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
.It \ea <alert character>
.It \er <carriage return>
A backslash followed by any other character maps to that character.
Represents the range of characters between the range endpoints, inclusively.
Represents all characters belonging to the defined character class.
.It alnum <alphanumeric characters>
.It alpha <alphabetic characters>
.It cntrl <control characters>
.It digit <numeric characters>
.It graph <graphic characters>
.It lower <lower-case alphabetic characters>
.It print <printable characters>
.It punct <punctuation characters>
.It space <space characters>
.It upper <upper-case characters>
.It xdigit <hexadecimal characters>
\." All classes may be used in
\." options are specified.
\." Otherwise, only the classes ``upper'' and ``lower'' may be used in
\." and then only when the corresponding class (``upper'' for ``lower''
\." and vice-versa) is specified in the same relative position in
With the exception of the ``upper'' and ``lower'' classes, characters
in the classes are in unspecified order.
In the ``upper'' and ``lower'' classes, characters are entered in
For specific information as to which ASCII characters are included
and related manual pages.
Represents all characters or collating (sorting) elements belonging to
the same equivalence class as
there is a secondary ordering within the equivalence class, the characters
are ordered in ascending sequence.
Otherwise, they are ordered after their encoded values.
An example of an equivalence class might be ``c'' and ``ch'' in Spanish;
English has no equivalence classes.
repeated occurrences of the character represented by
expression is only valid when it occurs in
is omitted or is zero, it is be interpreted as large enough to extend
sequence to the length of
has a leading zero, it is interpreted as an octal value, otherwise,
it's interpreted as a decimal value.
utility exits 0 on success, and >0 if an error occurs.
The following examples are shown as given to the shell:
Create a list of the words in file1, one per line, where a word is taken to
be a maximal string of letters.
.D1 Li "tr -cs \*q[:alpha:]\*q \*q\en\*q < file1"
Translate the contents of file1 to upper-case.
.D1 Li "tr \*q[:lower:]\*q \*q[:upper:]\*q < file1"
Strip out non-printable characters from file1.
.D1 Li "tr -cd \*q[:print:]\*q < file1"
System V has historically implemented character ranges using the syntax
``[c-c]'' instead of the ``c-c'' used by historic BSD implementations and
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 ``['' character in
to the ``['' character in
However, if the shell script is deleting or squeezing characters as in
the command ``tr -d [a-z]'', the characters ``['' and ``]'' will be
included in the deletion or compression list which would not have happened
under an 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
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,
options were ignored unless two strings were specified.
This implementation will not permit illegal syntax.
utility is expected to be
It should be noted that the feature wherein the last character of
is permitted by POSIX but is not required.
Shell scripts attempting to be portable to other POSIX systems should use
the ``[#*]'' convention instead of relying on this behavior.