xref: /freebsd/usr.bin/tr/tr.1 (revision 74bf4e164ba5851606a27d4feff27717452583e5)
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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
213.Dq Li [:lower:]
214appears in
215.Ar string1
216and
217.Dq Li [:upper:]
218appears in the same relative position in
219.Ar string2 ,
220it represents the characters pairs from the
221.Dv toupper
222mapping in the
223.Ev LC_CTYPE
224category of the current locale.
225When
226.Dq Li [:upper:]
227appears in
228.Ar string1
229and
230.Dq Li [:lower:]
231appears in the same relative position in
232.Ar string2 ,
233it represents the characters pairs from the
234.Dv tolower
235mapping in the
236.Ev LC_CTYPE
237category of the current locale.
238.Pp
239With the exception of case conversion,
240characters in the classes are in unspecified order.
241.Pp
242For specific information as to which
243.Tn ASCII
244characters are included
245in these classes, see
246.Xr ctype 3
247and related manual pages.
248.It [=equiv=]
249Represents all characters belonging to the same equivalence class as
250.Ar equiv ,
251ordered by their encoded values.
252.It [#*n]
253Represents
254.Ar n
255repeated occurrences of the character represented by
256.Ar # .
257This
258expression is only valid when it occurs in
259.Ar string2 .
260If
261.Ar n
262is omitted or is zero, it is be interpreted as large enough to extend
263.Ar string2
264sequence to the length of
265.Ar string1 .
266If
267.Ar n
268has a leading zero, it is interpreted as an octal value, otherwise,
269it's interpreted as a decimal value.
270.El
271.Sh ENVIRONMENT
272The
273.Ev LANG , LC_ALL , LC_CTYPE
274and
275.Ev LC_COLLATE
276environment variables affect the execution of
277.Nm
278as described in
279.Xr environ 7 .
280.Sh EXAMPLES
281The following examples are shown as given to the shell:
282.Pp
283Create a list of the words in file1, one per line, where a word is taken to
284be a maximal string of letters.
285.Pp
286.D1 Li "tr -cs \*q[:alpha:]\*q \*q\en\*q < file1"
287.Pp
288Translate the contents of file1 to upper-case.
289.Pp
290.D1 Li "tr \*q[:lower:]\*q \*q[:upper:]\*q < file1"
291.Pp
292(This should be preferred over the traditional
293.Ux
294idiom of
295.Ql "tr a-z A-Z" ,
296since it works correctly in all locales.)
297.Pp
298Strip out non-printable characters from file1.
299.Pp
300.D1 Li "tr -cd \*q[:print:]\*q < file1"
301.Pp
302Remove diacritical marks from all accented variants of the letter
303.Ql e :
304.Pp
305.Dl "tr \*q[=e=]\*q \*qe\*q"
306.Sh DIAGNOSTICS
307.Ex -std
308.Sh COMPATIBILITY
309Previous
310.Fx
311implementations of
312.Nm
313did not order characters in range expressions according to the current
314locale's collation order, making it possible to convert unaccented Latin
315characters (esp. as found in English text) from upper to lower case using
316the traditional
317.Ux
318idiom of
319.Ql "tr A-Z a-z" .
320Since
321.Nm
322now obeys the locale's collation order, this idiom may not produce
323correct results when there is not a 1:1 mapping between lower and
324upper case, or when the order of characters within the two cases differs.
325As noted in the
326.Sx EXAMPLES
327section above, the character class expressions
328.Ql "[:lower:]"
329and
330.Ql "[:upper:]"
331should be used instead of explicit character ranges like
332.Ql "a-z"
333and
334.Ql "A-Z" .
335.Pp
336System V has historically implemented character ranges using the syntax
337.Dq Li [c-c]
338instead of the
339.Dq Li c-c
340used by historic
341.Bx
342implementations and
343standardized by POSIX.
344System V shell scripts should work under this implementation as long as
345the range is intended to map in another range, i.e., the command
346.Dq Li "tr [a-z] [A-Z]"
347will work as it will map the
348.Ql \&[
349character in
350.Ar string1
351to the
352.Ql \&[
353character in
354.Ar string2 .
355However, if the shell script is deleting or squeezing characters as in
356the command
357.Dq Li "tr -d [a-z]" ,
358the characters
359.Ql \&[
360and
361.Ql \&]
362will be
363included in the deletion or compression list which would not have happened
364under a historic System V implementation.
365Additionally, any scripts that depended on the sequence
366.Dq Li a-z
367to
368represent the three characters
369.Ql a ,
370.Ql \&-
371and
372.Ql z
373will have to be
374rewritten as
375.Dq Li a\e-z .
376.Pp
377The
378.Nm
379utility has historically not permitted the manipulation of NUL bytes in
380its input and, additionally, stripped NUL's from its input stream.
381This implementation has removed this behavior as a bug.
382.Pp
383The
384.Nm
385utility has historically been extremely forgiving of syntax errors,
386for example, the
387.Fl c
388and
389.Fl s
390options were ignored unless two strings were specified.
391This implementation will not permit illegal syntax.
392.Sh STANDARDS
393The
394.Nm
395utility conforms to
396.St -p1003.1-2001 .
397.Pp
398It should be noted that the feature wherein the last character of
399.Ar string2
400is duplicated if
401.Ar string2
402has less characters than
403.Ar string1
404is permitted by POSIX but is not required.
405Shell scripts attempting to be portable to other POSIX systems should use
406the
407.Dq Li [#*]
408convention instead of relying on this behavior.
409The
410.Fl u
411option is an extension to the
412.St -p1003.1-2001
413standard.
414