Table of Contents

Name

tr - translate characters

Synopsis

tr [-c | -C][-s] string1 string2

tr -s [-c | -C] string1

tr -d [-c | -C] string1

tr -ds [-c | -C] string1 string2

Description

The tr utility shall copy the standard input to the standard output with substitution or deletion of selected characters. The options specified and the string1 and string2 operands shall control translations that occur while copying characters and single-character collating elements.

Options

The tr utility shall conform to the Base Definitions volume of IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.

The following options shall be supported:

-c
Complement the set of values specified by string1. See the EXTENDED DESCRIPTION section.
-C
Complement the set of characters specified by string1. See the EXTENDED DESCRIPTION section.
-d
Delete all occurrences of input characters that are specified by string1.
-s
Replace instances of repeated characters with a single character, as described in the EXTENDED DESCRIPTION section.

Operands

The following operands shall be supported:

string1, string2

Translation control strings. Each string shall represent a set of characters to be converted into an array of characters used for the translation. For a detailed description of how the strings are interpreted, see the EXTENDED DESCRIPTION section.

Stdin

The standard input can be any type of file.

Input Files

None.

Environment Variables

The following environment variables shall affect the execution of tr:

LANG
Provide a default value for the internationalization variables that are unset or null. (See the Base Definitions volume of IEEE Std 1003.1-2001, Section 8.2, Internationalization Variables for the precedence of internationalization variables used to determine the values of locale categories.)
LC_ALL
If set to a non-empty string value, override the values of all the other internationalization variables.
LC_COLLATE

Determine the locale for the behavior of range expressions and equivalence classes.

LC_CTYPE
Determine the locale for the interpretation of sequences of bytes of text data as characters (for example, single-byte as opposed to multi-byte characters in arguments) and the behavior of character classes.
LC_MESSAGES
Determine the locale that should be used to affect the format and contents of diagnostic messages written to standard error.
NLSPATH
Determine the location of message catalogs for the processing of LC_MESSAGES .

Asynchronous Events

Default.

Stdout

The tr output shall be identical to the input, with the exception of the specified transformations.

Stderr

The standard error shall be used only for diagnostic messages.

Output Files

None.

Extended Description

The operands string1 and string2 (if specified) define two arrays of characters. The constructs in the following list can be used to specify characters or single-character collating elements. If any of the constructs result in multi-character collating elements, tr shall exclude, without a diagnostic, those multi-character elements from the resulting array.

character
Any character not described by one of the conventions below shall represent itself.
\octal
Octal sequences can be used to represent characters with specific coded values. An octal sequence shall consist of a backslash followed by the longest sequence of one, two, or three-octal-digit characters (01234567). The sequence shall cause the value whose encoding is represented by the one, two, or three-digit octal integer to be placed into the array. If the size of a byte on the system is greater than nine bits, the valid escape sequence used to represent a byte is implementation-defined. Multi-byte characters require multiple, concatenated escape sequences of this type, including the leading ’\’ for each byte.
\character
The backslash-escape sequences in the Base Definitions volume of IEEE Std 1003.1-2001, Table 5-1, Escape Sequences and Associated Actions ( ’\\’ , ’\a’ , ’\b’ , ’\f’ , ’\n’ , ’\r’ , ’\t’ , ’\v’ ) shall be supported. The results of using any other character, other than an octal digit, following the backslash are unspecified.
c-c
In the POSIX locale, this construct shall represent the range of collating elements between the range endpoints (as long as neither endpoint is an octal sequence of the form \octal), inclusive, as defined by the collation sequence. The characters or collating elements in the range shall be placed in the array in ascending collation sequence. If the second endpoint precedes the starting endpoint in the collation sequence, it is unspecified whether the range of collating elements is empty, or this construct is treated as invalid. In locales other than the POSIX locale, this construct has unspecified behavior.

If either or both of the range endpoints are octal sequences of the form \octal, this shall represent the range of specific coded values between the two range endpoints, inclusive.

:class:
Represents all characters belonging to the defined character class, as defined by the current setting of the LC_CTYPE locale category. The following character class names shall be accepted when specified in string1:

=equiv=
x*n



Exit Status

Consequences of Errors

Application Usage




Examples




Rationale



Future Directions

See Also

Copyright

In addition, character class expressions of the form [: name:]
shall be recognized in those locales where the name


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