TR(1) User Commands TR(1)
NAME
tr - translate characters
SYNOPSIS
/usr/bin/tr [
-cds] [
string1 [
string2]]
/usr/xpg4/bin/tr [
-cs]
string1 string2 /usr/xpg4/bin/tr -s |
-d [
-c]
string1 /usr/xpg4/bin/tr -ds [
-c]
string1 string2 /usr/xpg6/bin/tr [
-c |
-C] [
-s]
string1 string2 /usr/xpg6/bin/tr -s [
-c |
-C]
string1 /usr/xpg6/bin/tr -d [
-c |
-C]
string1 /usr/xpg6/bin/tr -ds [
-c |
-C]
string1 string2DESCRIPTION
The
tr utility copies the standard input to the standard output with
substitution or deletion of selected characters. The options specified
and the
string1 and
string2 operands control translations that occur
while copying characters and single-character collating elements.
OPTIONS
The following options are supported:
-c Complements the set of values specified by
string1.
-C Complements the set of characters specified by
string1.
-d Deletes all occurrences of input characters that are specified by
string1.
-s Replaces instances of repeated characters with a single character.
When the
-d option is not specified:
o Each input character found in the array specified by
string1 is replaced by the character in the same relative position in
the array specified by
string2. When the array specified by
string2 is shorter than the one specified by
string1, the
results are unspecified.
o If the
-c option is specified, the complements of the values
specified by
string1 are placed in the array in ascending
order by binary value.
o If the
-C option is specified, the complements of the
characters specified by
string1 (the set of all characters in
the current character set, as defined by the current setting
of
LC_CTYPE, except for those actually specified in the
string1 operand) are placed in the array in ascending
collation sequence, as defined by the current setting of
LC_COLLATE.
o Because the order in which characters specified by character
class expressions or equivalence class expressions is
undefined, such expressions should only be used if the intent
is to map several characters into one. An exception is case
conversion, as described previously.
When the
-d option is specified:
o Input characters found in the array specified by
string1 are
deleted.
o When the
-C option is specified with
-d, all values except
those specified by
string1 are deleted. The contents of
string2 are ignored, unless the
-s option is also specified.
o If the
-c option is specified, the complements of the values
specified by
string1 are placed in the array in ascending
order by binary value.
o The same string cannot be used for both the
-d and the
-s option. When both options are specified, both
string1 (used
for deletion) and
string2 (used for squeezing) are required.
When the
-s option is specified, after any deletions or translations have
taken place, repeated sequences of the same character is replaced by one
occurrence of the same character, if the character is found in the array
specified by the last operand. If the last operand contains a character
class, such as the following example:
tr -s '[:space:]' the last operand's array contains all of the characters in that character
class. However, in a case conversion, as described previously, such as
tr -s '[:upper:]' '[:lower:]' the last operand's array contains only those characters defined as the
second characters in each of the
toupper or
tolower character pairs, as
appropriate. (See
toupper(3C) and
tolower(3C)).
An empty string used for
string1 or
string2 produces undefined results.
OPERANDS
The following operands are supported:
string1 string2 Translation control strings. Each string represents a set of
characters to be converted into an array of characters used
for the translation.
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 excludes,
without a diagnostic, those multi-character elements from the resulting
array.
character Any character not described by one of the conventions
below represents itself.
\octal Octal sequences can be used to represent characters with
specific coded values. An octal sequence consists of a
backslash followed by the longest sequence of one-, two-,
or three-octal-digit characters (01234567). The sequence
causes the character whose encoding is represented by the
one-, two- or three-digit octal integer to be placed into
the array. Multi-byte characters require multiple,
concatenated escape sequences of this type, including the
leading \ for each byte.
\character The backslash-escape sequences
\a,
\b,
\f,
\n,
\r,
\t, and
\v are supported. The results of using any other
character, other than an octal digit, following the
backslash are unspecified.
/usr/xpg4/bin/tr c-c /usr/bin/tr [c-c]
In the POSIX locale, this construct represents the range of
collating elements between the range endpoints (as long as
neither endpoint is an octal sequence of the form
\octal),
inclusively, as defined by the collation sequence. The
characters or collating elements in the range are 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, represents the range of specific coded
binary values between two range endpoints, inclusively.
[: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 are
accepted when specified in
string1:
alnum blank digit lower punct upper
alpha cntrl graph print space xdigit
In addition, character class expressions of the form
[:name:] are recognized in those locales where the
name keyword has been given a
charclass definition in the
LC_CTYPE category.
When both the
-d and
-s options are specified, any of the
character class names are accepted in
string2. Otherwise,
only character class names
lower or
upper are valid in
string2 and then only if the corresponding character class
upper and
lower, respectively, is specified in the same
relative position in
string1. Such a specification is
interpreted as a request for case conversion. When
[:lower:] appears in
string1 and
[:upper:] appears in
string2, the
arrays contain the characters from the
toupper mapping in
the
LC_CTYPE category of the current locale. When
[:upper:] appears in
string1 and
[:lower:] appears in
string2, the
arrays contain the characters from the
tolower mapping in
the
LC_CTYPE category of the current locale. The first
character from each mapping pair is in the array for
string1 and the second character from each mapping pair is in the
array for
string2 in the same relative position.
Except for case conversion, the characters specified by a
character class expression are placed in the array in an
unspecified order.
If the name specified for
class does not define a valid
character class in the current locale, the behavior is
undefined.
[=equiv=] Represents all characters or collating elements belonging to
the same equivalence class as
equiv, as defined by the
current setting of the
LC_COLLATE locale category. An
equivalence class expression is allowed only in
string1, or
in
string2 when it is being used by the combined
-d and
-s options. The characters belonging to the equivalence class
are placed in the array in an unspecified order.
[x*n]
Represents
n repeated occurrences of the character
x.
Because this expression is used to map multiple characters
to one, it is only valid when it occurs in
string2. If
n has
a leading
0, it is interpreted as an octal value. Otherwise,
it is interpreted as a decimal value.
If
n is omitted or is
0,
/usr/bin/tr interprets this as
huge;
/usr/xpg4/bin/tr and
/usr/xpg6/bin/tr interprets this
as large enough to extend the
string2-based sequence to the
length of the
string1-based sequence.
USAGE
See
largefile(7) for the description of the behavior of
tr when
encountering files greater than or equal to 2 Gbyte ( 2^31 bytes).
EXAMPLES
Example 1: Creating a list of words
The following example creates a list of all words in
file1, one per line
in
file2, where a word is taken to be a maximal string of letters.
tr -cs "[:alpha:]" "[\n*]" <file1 >file2 Example 2: Translating characters
This example translates all lower-case characters in
file1 to upper-case
and writes the results to standard output.
tr "[:lower:]" "[:upper:]" <file1 Notice that the caveat expressed in the corresponding example in XPG3 is
no longer in effect. This case conversion is now a special case that
employs the
tolower and
toupper classifications, ensuring that proper
mapping is accomplished (when the locale is correctly defined).
Example 3: Identifying equivalent characters
This example uses an equivalence class to identify accented variants of
the base character
e in
file1, which are stripped of diacritical marks
and written to
file2.
tr "[=e=]" e <file1 >file2ENVIRONMENT VARIABLES
See
environ(7) for descriptions of the following environment variables
that affect the execution of
tr:
LANG,
LC_ALL,
LC_COLLATE,
LC_CTYPE,
LC_MESSAGES, and
NLSPATH.
EXIT STATUS
The following exit values are returned:
0 All input was processed successfully.
>0 An error occurred.
ATTRIBUTES
See
attributes(7) for descriptions of the following attributes:
/usr/bin/tr +---------------+-----------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+-----------------+
|CSI | Enabled |
+---------------+-----------------+
/usr/xpg4/bin/tr +--------------------+-------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-------------------+
|CSI | Enabled |
+--------------------+-------------------+
|Interface Stability | Committed |
+--------------------+-------------------+
|Standard | See
standards(7). |
+--------------------+-------------------+
/usr/xpg6/bin/tr +--------------------+-------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-------------------+
|CSI | Enabled |
+--------------------+-------------------+
|Interface Stability | Committed |
+--------------------+-------------------+
|Standard | See
standards(7). |
+--------------------+-------------------+
SEE ALSO
ed(1),
sed(1),
sh(1),
tolower(3C),
toupper(3C),
ascii(7),
attributes(7),
environ(7),
largefile(7),
regex(7),
standards(7)NOTES
Unlike some previous versions,
/usr/xpg4/bin/tr correctly processes
NUL characters in its input stream.
NUL characters can be stripped by using
tr -d '\000'.
June 13, 2021
TR(1)