TR(1)TR(1)NAMEtr - 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 string2
DESCRIPTION
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 charac‐
ter.
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 char‐
acters 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 colla‐
tion sequence, as defined by the current setting of LC_COL‐
LATE.
o Because the order in which characters specified by character
class expressions or equivalence class expressions is unde‐
fined, 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 charac‐
ter 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 con‐
structs 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 repre‐
sented 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 spe‐
cific coded binary values between two range endpoints,
inclusively.
[:class:]
Represents all characters belonging to the defined charac‐
ter 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 toup‐
per 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 cur‐
rent 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. Oth‐
erwise, 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 thestring2-based sequence
to the length of the string1-based sequence.
USAGE
See largefile(5) for the description of the behavior of tr when encoun‐
tering 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 >file2
ENVIRONMENT VARIABLES
See environ(5) 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(5) 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(5). │
└────────────────────┴───────────────────┘
/usr/xpg6/bin/tr
┌────────────────────┬───────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├────────────────────┼───────────────────┤
│CSI │ Enabled │
├────────────────────┼───────────────────┤
│Interface Stability │ Committed │
├────────────────────┼───────────────────┤
│Standard │ See standards(5). │
└────────────────────┴───────────────────┘
SEE ALSOed(1), sed(1), sh(1), tolower(3C), toupper(3C), ascii(5),
attributes(5), environ(5), largefile(5), regex(5), standards(5)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'.
Mar 3, 2009 TR(1)
