tr

tr is a command-line utility used to translate or delete characters from standard input and write the result to standard output. It is commonly used for transforming text, such as changing case, deleting characters, or replacing characters.

Basic Syntax

tr [options] set1 [set2]

Commonly Used Options

-c: Complement the set of characters in set1.
-d: Delete characters in set1.
-s: Squeeze repeated characters in set1.
-t: Truncate set1 to the length of set2.

Examples

Basic Translation

Translate lowercase letters to uppercase:

echo "hello world" | tr 'a-z' 'A-Z'

Delete Characters

Delete all digits from the input:

echo "hello123" | tr -d '0-9'

Squeeze Repeated Characters

Squeeze multiple spaces into a single space:

echo "hello world" | tr -s ' '

Complement Set

Replace all characters except digits with asterisks:

echo "hello123" | tr -c '0-9' '*'

Translate and Delete

Translate lowercase to uppercase and delete digits:

echo "hello123" | tr 'a-z0-9' 'A-Z'

Using Character Classes

Translate all lowercase letters to uppercase using character classes:

echo "hello world" | tr '[:lower:]' '[:upper:]'

Using Ranges

Translate digits to letters:

echo "12345" | tr '0-9' 'a-j'

Truncate Set1

Translate the first three letters to uppercase, ignoring the rest:

echo "abcdef" | tr -t 'a-z' 'A-C'

Conclusion

tr is a versatile tool for translating, deleting, and squeezing characters in text. Understanding its options allows for efficient and powerful text manipulation directly from the command line.

Last modified: 14 December 2024