The following options are available:
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> |
alnum <alphanumeric characters> |
alpha <alphabetic characters> |
blank <blank characters> |
cntrl <control characters> |
digit <numeric characters> |
graph <graphic characters> |
lower <lower-case alphabetic characters> |
print <printable characters> |
punct <punctuation characters> |
space <space characters> |
upper <upper-case characters> |
xdigit <hexadecimal characters> |
With the exception of the ``upper'' and ``lower'' classes, characters in the classes are in unspecified order. In the ``upper'' and ``lower'' classes, characters are entered in ascending order.
For specific information as to which ASCII characters are included in these classes, see ctype(3) and related manual pages.
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
Strip out non-printable characters from
file1:
tr -cd "[:print:]" < file1
AT&T
System V UNIX
has historically implemented character ranges using the syntax
``[c-c]''
instead of the
``c-c''
used by historic
BSD
implementations and standardized by POSIX.
AT&T
System V UNIX
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 an historic
AT&T
System V UNIX
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.
tr should be internationalized.