TR(I) 9/24/73 TR(I)
tr - transliterate
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. If string2 is short,
it is padded with corresponding characters from string1.
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 001 through
377 octal. -d deletes all input characters not in string1.
-s squeezes all strings of repeated output characters that
are in string2 to single characters.
The following abbreviation conventions may be used to
introduce ranges of characters or repeated characters into
-b] stands for the string of characters whose ascii codes
run from character a to character b.
[a*n], where n is an integer or empty, stands for n-fold
repetition of character a. n is taken to be octal or
decimal according as its first digit is or is not zero. A
zero or missing n is taken to be huge; this facility is
useful for padding string2.
The escape character `\' may be used as in sh to remove
special meaning from any character in a string. In
addition, `\' followed by 1, 2 or 3 octal digits stands for
the character whose ascii code is given by those digits.
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 strings are quoted to
protect the special characters from interpretation by the
Shell; 012 is the ascii code for newline.
tr -cs "[A-Z][a-z]" "[\012*]" <file1 >file2
sh(I), ed(I), ascii(VII)
Won't handle ascii NUL.
Also, Kernighan's Lemma can really bite you; try looking for
strings which have \ and * in them.