NAME
tr - translate character codes
SYNOPSIS
tr [-cds] [string1] [string2]
OPTIONS
-c Complement the set of characters in string1
-d Delete all characters specified in string1
-s Squeeze all runs of characters in string1 to one char-
acter
EXAMPLES
tr 'A-Z' 'a-z' <x >y
# Convert upper case to lower case
tr -d '0123456789' <f1 >f2
# Delete all digits from f1
DESCRIPTION
Tr performs simple character translation. When no flag is
specified, each character in string1 is mapped onto the
corresponding character in string2 .
There are two types of tr out there, one that requires [ and
] for character classes, and one that does not. Here is
what the example above would look like for a tr that needs
the brackets:
tr '[A-Z]' '[a-z]' <x >y
Use [ and ] if you want to be portable, because a tr that
doesn't need them will still accept the syntax and mind-
lessly translate [ into [ and ] into ].