xref: /freebsd/usr.bin/tr/tr.1 (revision 0b651019b450cfc36d4a483f56fd015ee7c09234)
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35.\"     @(#)tr.1	8.1 (Berkeley) 6/6/93
36.\" $FreeBSD$
37.\"
38.Dd July 23, 2004
39.Dt TR 1
40.Os
41.Sh NAME
42.Nm tr
43.Nd translate characters
44.Sh SYNOPSIS
45.Nm
46.Op Fl Ccsu
47.Ar string1 string2
48.Nm
49.Op Fl Ccu
50.Fl d
51.Ar string1
52.Nm
53.Op Fl Ccu
54.Fl s
55.Ar string1
56.Nm
57.Op Fl Ccu
58.Fl ds
59.Ar string1 string2
60.Sh DESCRIPTION
61The
62.Nm
63utility copies the standard input to the standard output with substitution
64or deletion of selected characters.
65.Pp
66The following options are available:
67.Bl -tag -width Ds
68.It Fl C
69Complement the set of characters in
70.Ar string1 ,
71that is
72.Dq Fl C Li ab
73includes every character except for
74.Ql a
75and
76.Ql b .
77.It Fl c
78Same as
79.Fl C
80but complement the set of values in
81.Ar string1 .
82.It Fl d
83Delete characters in
84.Ar string1
85from the input.
86.It Fl s
87Squeeze multiple occurrences of the characters listed in the last
88operand (either
89.Ar string1
90or
91.Ar string2 )
92in the input into a single instance of the character.
93This occurs after all deletion and translation is completed.
94.It Fl u
95Guarantee that any output is unbuffered.
96.El
97.Pp
98In the first synopsis form, the characters in
99.Ar string1
100are translated into the characters in
101.Ar string2
102where the first character in
103.Ar string1
104is translated into the first character in
105.Ar string2
106and so on.
107If
108.Ar string1
109is longer than
110.Ar string2 ,
111the last character found in
112.Ar string2
113is duplicated until
114.Ar string1
115is exhausted.
116.Pp
117In the second synopsis form, the characters in
118.Ar string1
119are deleted from the input.
120.Pp
121In the third synopsis form, the characters in
122.Ar string1
123are compressed as described for the
124.Fl s
125option.
126.Pp
127In the fourth synopsis form, the characters in
128.Ar string1
129are deleted from the input, and the characters in
130.Ar string2
131are compressed as described for the
132.Fl s
133option.
134.Pp
135The following conventions can be used in
136.Ar string1
137and
138.Ar string2
139to specify sets of characters:
140.Bl -tag -width [:equiv:]
141.It character
142Any character not described by one of the following conventions
143represents itself.
144.It \eoctal
145A backslash followed by 1, 2 or 3 octal digits represents a character
146with that encoded value.
147To follow an octal sequence with a digit as a character, left zero-pad
148the octal sequence to the full 3 octal digits.
149.It \echaracter
150A backslash followed by certain special characters maps to special
151values.
152.Pp
153.Bl -column "\ea"
154.It "\ea	<alert character>
155.It "\eb	<backspace>
156.It "\ef	<form-feed>
157.It "\en	<newline>
158.It "\er	<carriage return>
159.It "\et	<tab>
160.It "\ev	<vertical tab>
161.El
162.Pp
163A backslash followed by any other character maps to that character.
164.It c-c
165For non-octal range endpoints
166represents the range of characters between the range endpoints, inclusive,
167in ascending order,
168as defined by the collation sequence.
169If either or both of the range endpoints are octal sequences, it
170represents the range of specific coded values between the
171range endpoints, inclusive.
172.Pp
173.Bf Em
174See the COMPATIBILITY section below for an important note regarding
175differences in the way the current
176implementation interprets range expressions differently from
177previous implementations.
178.Ef
179.It [:class:]
180Represents all characters belonging to the defined character class.
181Class names are:
182.Pp
183.Bl -column "xdigit"
184.It "alnum	<alphanumeric characters>
185.It "alpha	<alphabetic characters>
186.It "cntrl	<control characters>
187.It "digit	<numeric characters>
188.It "graph	<graphic characters>
189.It "lower	<lower-case alphabetic characters>
190.It "print	<printable characters>
191.It "punct	<punctuation characters>
192.It "space	<space characters>
193.It "upper	<upper-case characters>
194.It "xdigit	<hexadecimal characters>
195.El
196.Pp
197.\" All classes may be used in
198.\" .Ar string1 ,
199.\" and in
200.\" .Ar string2
201.\" when both the
202.\" .Fl d
203.\" and
204.\" .Fl s
205.\" options are specified.
206.\" Otherwise, only the classes ``upper'' and ``lower'' may be used in
207.\" .Ar string2
208.\" and then only when the corresponding class (``upper'' for ``lower''
209.\" and vice-versa) is specified in the same relative position in
210.\" .Ar string1 .
211.\" .Pp
212When ``[:lower:]'' appears in
213.Ar string1
214and ``[:upper:]'' appears in the same relative position in
215.Ar string2 ,
216it represents the characters pairs from the
217.Dv toupper
218mapping in the
219.Ev LC_CTYPE
220category of the current locale.
221When ``[:upper:]'' appears in
222.Ar string1
223and ``[:lower:]'' appears in the same relative position in
224.Ar string2 ,
225it represents the characters pairs from the
226.Dv tolower
227mapping in the
228.Ev LC_CTYPE
229category of the current locale.
230.Pp
231With the exception of case conversion,
232characters in the classes are in unspecified order.
233.Pp
234For specific information as to which
235.Tn ASCII
236characters are included
237in these classes, see
238.Xr ctype 3
239and related manual pages.
240.It [=equiv=]
241Represents all characters belonging to the same equivalence class as
242.Ar equiv ,
243ordered by their encoded values.
244.It [#*n]
245Represents
246.Ar n
247repeated occurrences of the character represented by
248.Ar # .
249This
250expression is only valid when it occurs in
251.Ar string2 .
252If
253.Ar n
254is omitted or is zero, it is be interpreted as large enough to extend
255.Ar string2
256sequence to the length of
257.Ar string1 .
258If
259.Ar n
260has a leading zero, it is interpreted as an octal value, otherwise,
261it's interpreted as a decimal value.
262.El
263.Sh ENVIRONMENT
264The
265.Ev LANG , LC_ALL , LC_CTYPE
266and
267.Ev LC_COLLATE
268environment variables affect the execution of
269.Nm
270as described in
271.Xr environ 7 .
272.Sh EXAMPLES
273The following examples are shown as given to the shell:
274.Pp
275Create a list of the words in file1, one per line, where a word is taken to
276be a maximal string of letters.
277.Pp
278.D1 Li "tr -cs \*q[:alpha:]\*q \*q\en\*q < file1"
279.Pp
280Translate the contents of file1 to upper-case.
281.Pp
282.D1 Li "tr \*q[:lower:]\*q \*q[:upper:]\*q < file1"
283.Pp
284(This should be preferred over the traditional
285.Ux
286idiom of
287.Ql "tr a-z A-Z" ,
288since it works correctly in all locales.)
289.Pp
290Strip out non-printable characters from file1.
291.Pp
292.D1 Li "tr -cd \*q[:print:]\*q < file1"
293.Pp
294Remove diacritical marks from all accented variants of the letter
295.Ql e :
296.Pp
297.Dl "tr \*q[=e=]\*q \*qe\*q"
298.Sh DIAGNOSTICS
299.Ex -std
300.Sh COMPATIBILITY
301Previous
302.Fx
303implementations of
304.Nm
305did not order characters in range expressions according to the current
306locale's collation order, making it possible to convert unaccented Latin
307characters (esp. as found in English text) from upper to lower case using
308the traditional
309.Ux
310idiom of
311.Ql "tr A-Z a-z" .
312Since
313.Nm
314now obeys the locale's collation order, this idiom may not produce
315correct results when there is not a 1:1 mapping between lower and
316upper case, or when the order of characters within the two cases differs.
317As noted in the
318.Sx EXAMPLES
319section above, the character class expressions
320.Ql "[:lower:]"
321and
322.Ql "[:upper:]"
323should be used instead of explicit character ranges like
324.Ql "a-z"
325and
326.Ql "A-Z" .
327.Pp
328System V has historically implemented character ranges using the syntax
329``[c-c]'' instead of the ``c-c'' used by historic
330.Bx
331implementations and
332standardized by POSIX.
333System V shell scripts should work under this implementation as long as
334the range is intended to map in another range, i.e., the command
335``tr [a-z] [A-Z]'' will work as it will map the ``['' character in
336.Ar string1
337to the ``['' character in
338.Ar string2 .
339However, if the shell script is deleting or squeezing characters as in
340the command ``tr -d [a-z]'', the characters ``['' and ``]'' will be
341included in the deletion or compression list which would not have happened
342under a historic System V implementation.
343Additionally, any scripts that depended on the sequence ``a-z'' to
344represent the three characters ``a'', ``-'' and ``z'' will have to be
345rewritten as ``a\e-z''.
346.Pp
347The
348.Nm
349utility has historically not permitted the manipulation of NUL bytes in
350its input and, additionally, stripped NUL's from its input stream.
351This implementation has removed this behavior as a bug.
352.Pp
353The
354.Nm
355utility has historically been extremely forgiving of syntax errors,
356for example, the
357.Fl c
358and
359.Fl s
360options were ignored unless two strings were specified.
361This implementation will not permit illegal syntax.
362.Sh STANDARDS
363The
364.Nm
365utility conforms to
366.St -p1003.1-2001 .
367.Pp
368It should be noted that the feature wherein the last character of
369.Ar string2
370is duplicated if
371.Ar string2
372has less characters than
373.Ar string1
374is permitted by POSIX but is not required.
375Shell scripts attempting to be portable to other POSIX systems should use
376the ``[#*]'' convention instead of relying on this behavior.
377The
378.Fl u
379option is an extension to the
380.St -p1003.1-2001
381standard.
382