TR(1) General Commands Manual TR(1)
tr - translate characters
tr [ -cds ] [ string1 [ string2 ] ]
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 duplicat-
ing 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
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 '