TR(1) | General Commands Manual | TR(1) |
tr
— translate
characters
tr |
[-Ccsu ] string1
string2 |
tr |
[-Ccu ] -d
string1 |
tr |
[-Ccu ] -s
string1 |
tr |
[-Ccu ] -ds
string1 string2 |
The tr
utility copies the standard input
to the standard output with substitution or deletion of selected
characters.
The following options are available:
-C
-C
ab
”
includes every character except for
‘a
’ and
‘b
’.-c
-C
but complement the set of values in
string1.-d
-s
-u
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
string1 are compressed as described for the
-s
option.
In the fourth synopsis form, the characters in
string1 are deleted from the input, and the characters
in string2 are compressed as described for the
-s
option.
The following conventions can be used in string1 and string2 to specify sets of characters:
\a | <alert character> |
\b | <backspace> |
\f | <form-feed> |
\n | <newline> |
\r | <carriage return> |
\t | <tab> |
\v | <vertical tab> |
A backslash followed by any other character maps to that character.
alnum | <alphanumeric characters> |
alpha | <alphabetic characters> |
blank | <whitespace characters> |
cntrl | <control characters> |
digit | <numeric characters> |
graph | <graphic characters> |
ideogram | <ideographic characters> |
lower | <lower-case alphabetic characters> |
phonogram | <phonographic characters> |
<printable characters> | |
punct | <punctuation characters> |
rune | <valid characters> |
space | <space characters> |
special | <special characters> |
upper | <upper-case characters> |
xdigit | <hexadecimal characters> |
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.
The LANG
, LC_ALL
,
LC_CTYPE
and LC_COLLATE
environment variables affect the execution of tr
as
described in environ(7).
The tr
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.
tr -cs "[:alpha:]"
"\n" < file1
Translate the contents of file1 to upper-case.
tr "[:lower:]"
"[:upper:]" < file1
(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.
tr -cd "[:print:]" <
file1
Remove diacritical marks from all accented variants of the letter
‘e
’:
tr "[=e=]"
"e"
Previous FreeBSD implementations of
tr
did not order characters in range expressions
according to the current locale's collation order, making it possible to
convert unaccented Latin characters (esp. as found in English text) from
upper to lower case using the traditional UNIX idiom
of “tr A-Z a-z
”. Since
tr
now obeys the locale's collation order, this
idiom may not produce correct results when there is not a 1:1 mapping
between lower and upper case, or when the order of characters within the two
cases differs. As noted in the EXAMPLES
section above, the character class expressions
“[:lower:]
” and
“[:upper:]
” should be used instead of
explicit character ranges like “a-z
”
and “A-Z
”.
“[=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 ‘[
’ character in
string1 to the
‘[
’ character in
string2. 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 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.
The tr
utility has historically been
extremely forgiving of syntax errors, for example, the
-c
and -s
options were
ignored unless two strings were specified. This implementation will not
permit illegal syntax.
The tr
utility conforms to
IEEE Std 1003.1-2001 (“POSIX.1”). The
“ideogram”, “phonogram”, “rune”,
and “special” character classes are extensions.
It should be noted that the feature wherein the last character of
string2 is duplicated if string2
has less characters than string1 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. The
-u
option is an extension to the
IEEE Std 1003.1-2001 (“POSIX.1”)
standard.
October 13, 2006 | macOS 14.6 |