NAME
tr - translate characters

SYNOPSIS
tr [ -cds ] [ string1 [ string2 ] ]

DESCRIPTION
Tr copies the standard input to the standard output with
substitution or deletion of selected characters. Input characters
found in string1 are mapped into the corresponding characters of
string2. When string2 is short it is padded to the length of
string1 by duplicating its last character. Any combination of the
options -cds may be used: -c complements the set of characters in
string1 with respect to the universe of characters whose ASCII
codes are 01 through 0377 octal; -d deletes all input characters in
string1; -s squeezes all strings of repeated output characters that
are in string2 to single characters.

In either string the notation a-b means a range of characters from
a to b in increasing ASCII order. The character ‘´ followed by 1,
2 or 3 octal digits stands for the character whose ASCII code is
given by those digits. A ‘´ followed by any other character
stands for that character.

The following example creates a list of all the words in ‘file1’
one per line in ‘file2’, where a word is taken to be a maximal
string of alphabetics. The second string is quoted to protect ‘´
from the Shell. 012 is the ASCII code for newline.

tr -cs A-Za-z ’ 12’ <file1 >file2

SEE ALSO
ed(1), ascii(7), expand(1)

BUGS
Won’t handle ASCII NUL in string1 or string2; always deletes NUL
from input.