tr(1) — USER COMMANDS
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. 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 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 the strings:
[a−z] Stands for the string of characters whose ASCII codes run from character a to character z, inclusive.
[a∗n] Stands for n repetitions of a. If the first digit of n is 0, n is considered octal; otherwise, n is taken to be decimal. 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 the shell 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.
EXAMPLE
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
INTERNATIONAL FUNCTIONS
tr can process characters from supplementary code sets. Characters specified are searched for and translated in character units, not bytes.
The semantics of the "[x-y]" notation takes after the range specification of the regular expression syntax.
When octal notation with the backslash (\) escape character is used, a backslash is placed before each byte of characters from supplementary code set.
SEE ALSO
NOTES
Will not handle ASCII NUL in string1 or string2; always deletes NUL from input.
— Directory and File Management Utilities