freebsd/usr.bin/tr/tr.1

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.\"     @(#)tr.1	8.1 (Berkeley) 6/6/93
.\" $FreeBSD$
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.Dd July 23, 2004
.Dt TR 1
.Os
.Sh NAME
.Nm tr
.Nd translate characters
.Sh SYNOPSIS
.Nm
.Op Fl Ccsu
.Ar string1 string2
.Nm
.Op Fl Ccu
.Fl d
.Ar string1
.Nm
.Op Fl Ccu
.Fl s
.Ar string1
.Nm
.Op Fl Ccu
.Fl ds
.Ar string1 string2
.Sh DESCRIPTION
The
.Nm
utility copies the standard input to the standard output with substitution
or deletion of selected characters.
.Pp
The following options are available:
.Bl -tag -width Ds
.It Fl C
Complement the set of characters in
.Ar string1 ,
that is
.Dq Fl C Li ab
includes every character except for
.Ql a
and
.Ql b .
.It Fl c
Same as
.Fl C
but complement the set of values in
.Ar string1 .
.It Fl d
Delete characters in
.Ar string1
from the input.
.It Fl s
Squeeze multiple occurrences of the characters listed in the last
operand (either
.Ar string1
or
.Ar string2 )
in the input into a single instance of the character.
This occurs after all deletion and translation is completed.
.It Fl u
Guarantee that any output is unbuffered.
.El
.Pp
In the first synopsis form, the characters in
.Ar string1
are translated into the characters in
.Ar string2
where the first character in
.Ar string1
is translated into the first character in
.Ar string2
and so on.
If
.Ar string1
is longer than
.Ar string2 ,
the last character found in
.Ar string2
is duplicated until
.Ar string1
is exhausted.
.Pp
In the second synopsis form, the characters in
.Ar string1
are deleted from the input.
.Pp
In the third synopsis form, the characters in
.Ar string1
are compressed as described for the
.Fl s
option.
.Pp
In the fourth synopsis form, the characters in
.Ar string1
are deleted from the input, and the characters in
.Ar string2
are compressed as described for the
.Fl s
option.
.Pp
The following conventions can be used in
.Ar string1
and
.Ar string2
to specify sets of characters:
.Bl -tag -width [:equiv:]
.It character
Any character not described by one of the following conventions
represents itself.
.It \eoctal
A backslash followed by 1, 2 or 3 octal digits represents a character
with that encoded value.
To follow an octal sequence with a digit as a character, left zero-pad
the octal sequence to the full 3 octal digits.
.It \echaracter
A backslash followed by certain special characters maps to special
values.
.Pp
.Bl -column "\ea"
.It "\ea	<alert character>
.It "\eb	<backspace>
.It "\ef	<form-feed>
.It "\en	<newline>
.It "\er	<carriage return>
.It "\et	<tab>
.It "\ev	<vertical tab>
.El
.Pp
A backslash followed by any other character maps to that character.
.It c-c
For non-octal range endpoints
represents the range of characters between the range endpoints, inclusive,
in ascending order,
as defined by the collation sequence.
If either or both of the range endpoints are octal sequences, it
represents the range of specific coded values between the
range endpoints, inclusive.
.Pp
.Bf Em
See the COMPATIBILITY section below for an important note regarding
differences in the way the current
implementation interprets range expressions differently from
previous implementations.
.Ef
.It [:class:]
Represents all characters belonging to the defined character class.
Class names are:
.Pp
.Bl -column "xdigit"
.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>
.El
.Pp
.\" All classes may be used in
.\" .Ar string1 ,
.\" and in
.\" .Ar string2
.\" when both the
.\" .Fl d
.\" and
.\" .Fl s
.\" options are specified.
.\" Otherwise, only the classes ``upper'' and ``lower'' may be used in
.\" .Ar string2
.\" and then only when the corresponding class (``upper'' for ``lower''
.\" and vice-versa) is specified in the same relative position in
.\" .Ar string1 .
.\" .Pp
When
.Dq Li [:lower:]
appears in
.Ar string1
and
.Dq Li [:upper:]
appears in the same relative position in
.Ar string2 ,
it represents the characters pairs from the
.Dv toupper
mapping in the
.Ev LC_CTYPE
category of the current locale.
When
.Dq Li [:upper:]
appears in
.Ar string1
and
.Dq Li [:lower:]
appears in the same relative position in
.Ar string2 ,
it represents the characters pairs from the
.Dv tolower
mapping in the
.Ev LC_CTYPE
category of the current locale.
.Pp
With the exception of case conversion,
characters in the classes are in unspecified order.
.Pp
For specific information as to which
.Tn ASCII
characters are included
in these classes, see
.Xr ctype 3
and related manual pages.
.It [=equiv=]
Represents all characters belonging to the same equivalence class as
.Ar equiv ,
ordered by their encoded values.
.It [#*n]
Represents
.Ar n
repeated occurrences of the character represented by
.Ar # .
This
expression is only valid when it occurs in
.Ar string2 .
If
.Ar n
is omitted or is zero, it is be interpreted as large enough to extend
.Ar string2
sequence to the length of
.Ar string1 .
If
.Ar n
has a leading zero, it is interpreted as an octal value, otherwise,
it's interpreted as a decimal value.
.El
.Sh ENVIRONMENT
The
.Ev LANG , LC_ALL , LC_CTYPE
and
.Ev LC_COLLATE
environment variables affect the execution of
.Nm
as described in
.Xr environ 7 .
.Sh EXAMPLES
The following examples are shown as given to the shell:
.Pp
Create a list of the words in file1, one per line, where a word is taken to
be a maximal string of letters.
.Pp
.D1 Li "tr -cs \*q[:alpha:]\*q \*q\en\*q < file1"
.Pp
Translate the contents of file1 to upper-case.
.Pp
.D1 Li "tr \*q[:lower:]\*q \*q[:upper:]\*q < file1"
.Pp
(This should be preferred over the traditional
.Ux
idiom of
.Ql "tr a-z A-Z" ,
since it works correctly in all locales.)
.Pp
Strip out non-printable characters from file1.
.Pp
.D1 Li "tr -cd \*q[:print:]\*q < file1"
.Pp
Remove diacritical marks from all accented variants of the letter
.Ql e :
.Pp
.Dl "tr \*q[=e=]\*q \*qe\*q"
.Sh DIAGNOSTICS
.Ex -std
.Sh COMPATIBILITY
Previous
.Fx
implementations of
.Nm
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
.Ux
idiom of
.Ql "tr A-Z a-z" .
Since
.Nm
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
.Sx EXAMPLES
section above, the character class expressions
.Ql "[:lower:]"
and
.Ql "[:upper:]"
should be used instead of explicit character ranges like
.Ql "a-z"
and
.Ql "A-Z" .
.Pp
System V has historically implemented character ranges using the syntax
.Dq Li [c-c]
instead of the
.Dq Li c-c
used by historic
.Bx
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
.Dq Li "tr [a-z] [A-Z]"
will work as it will map the
.Ql \&[
character in
.Ar string1
to the
.Ql \&[
character in
.Ar string2 .
However, if the shell script is deleting or squeezing characters as in
the command
.Dq Li "tr -d [a-z]" ,
the characters
.Ql \&[
and
.Ql \&]
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
.Dq Li a-z
to
represent the three characters
.Ql a ,
.Ql \&-
and
.Ql z
will have to be
rewritten as
.Dq Li a\e-z .
.Pp
The
.Nm
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.
.Pp
The
.Nm
utility has historically been extremely forgiving of syntax errors,
for example, the
.Fl c
and
.Fl s
options were ignored unless two strings were specified.
This implementation will not permit illegal syntax.
.Sh STANDARDS
The
.Nm
utility conforms to
.St -p1003.1-2001 .
.Pp
It should be noted that the feature wherein the last character of
.Ar string2
is duplicated if
.Ar string2
has less characters than
.Ar string1
is permitted by POSIX but is not required.
Shell scripts attempting to be portable to other POSIX systems should use
the
.Dq Li [#*]
convention instead of relying on this behavior.
The
.Fl u
option is an extension to the
.St -p1003.1-2001
standard.