tr(1) General Commands Manual tr(1)
Name
tr - translate characters
Syntax
tr [-cds] [string1[string2]]
Description
The command 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 dupli-
cating 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 0 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 backslash 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 '