Translate, squeeze, and/or delete characters. Copies the standard input to the standard output with substitution or deletion of selected characters.

      tr [-Ccsu] string1 string2
      tr [-Ccu] -d string1
      tr [-Ccu] -s string1
      tr [-Ccu] -ds string1 string2

   -C     Complement the set of characters in string1, that is '-C ab'
          includes every character except for 'a' and 'b'.

   -c     Same as -C but complement the set of byte values in string1.

   -d     Delete characters in string1 from the input.

   -s     Squeeze multiple occurrences of the characters listed in the last
          instance of the character.  This occurs after all deletion and
          translation is completed.

   -u     Guarantee that any output is unbuffered.

     longer than string2, the last character found in string2 is duplicated
     until string1 is exhausted.

     the input.

     described for the -s option.

     the -s option.

     The following conventions can be used in string1 and string2 to specify
     sets of characters:

     character Any character not described by one of the following conven-
     tions represents itself.

     character with that encoded value.  To follow an octal
     sequence to the full 3 octal digits.

     A backslash followed by certain special characters maps to
     special values.

     \a    <alert character>
     \b    <backspace>
     \f    <form-feed>
     \n    <newline>
     \r    <carriage return>
     \t    <tab>
     \v    <vertical tab>

     A backslash followed by any other character maps to that character.

     c-c Represents the range of characters between the range end-points, inclusively.

     class. Class names are:

     alnum   <alphanumeric characters>
     alpha   <alphabetic characters>
     cntrl   <control characters>

     digit   <numeric characters>
     graph   <graphic characters>
     lower   <lower-case alphabetic characters>
     print   <printable characters>
     punct   <punctuation characters>

     space   <space characters>
     upper   <upper-case characters>
     xdigit   <hexadecimal characters>

     With the exception of the `upper' and `lower' classes,
     characters in the classes are in unspecified order.  In the
     `upper' and `lower' classes, characters are entered in
     ascending order.

     For specific information as to which ASCII characters are

     class as equiv, ordered by their encoded values.

     by #.  This expression is only valid when it occurs in
     large enough to extend string2 sequence to the length of
     octal value, otherwise, it's interpreted as a decimal value.


     The LANG, LC_ALL, LC_CTYPE and LC_COLLATE environment variables affect
     the execution of tr as described in environ(7).

The tr utility has historically been extremely forgiving of syntax errors, for example, the -c and -s options were ignored unless two strings were specified. This implementation will not permit illegal syntax.

The tr utility has historically not permitted the manipulation of NUL bytes in its input and, additionally, stripped NUL's from its input stream. This implementation has removed this behavior as a bug.

Exits 0 on success, and >0 if an error occurs


Swap the case of a string:
$ echo "Hello World" | tr "A-Za-z" "a-zA-Z"

Make an entire file uppercase:
$ cat file_of_lower_case_text | tr "[a-z]" "[A-Z]"
$ tr "[:lower:]" "[:upper:]" < file_of_lower_case_text

Make a string lower case:
$ echo "Hello World" | tr "[:upper:]" "[:lower:]"
hello world

As a function
$ toLower() {
 echo $1 | tr "[:upper:]" "[:lower:]"

$ toLower SomeMixEDCaseText

Swap braces with parentheses and vice versa:
$ echo "brackets demo(){}swap" | tr '{}()' '(){}'
brackets demo{}()swap

ROT 13 a string

$ echo 'Hello world' | tr 'A-Za-z' 'N-ZA-Mn-za-m'
Uryyb jbeyq

$ echo 'Uryyb jbeyq' | tr 'A-Za-z' 'N-ZA-Mn-za-m'
Hello world

Split the path into its elements
$ echo $PATH | tr ":" "\n" | sort

Create a list of the words in file1, one per line, where a word is taken to be a maximal string of letters.
$ tr -cs "[:alpha:]" "\n" < file1

Generate a 20 digit random password and copy it to the clipboard:
$ LC_ALL=C tr -dc "[:alpha:][:alnum:]" < /dev/urandom | head -c 20 | pbcopy

Strip out non-printable characters from file1.
$ tr -cd "[:print:]" < file1

Remove diacritical marks from all accented variants of the letter 'e':
$ tr "[=e=]" "e"

“Chance is always powerful. - Let your hook be always cast; in the pool where you least expect it, there will be a fish” ~ Ovid

Related macOS commands:

awk - Find and Replace text within file(s).

Copyright © 1999-2020
Some rights reserved