Master the Linux ‘tr’ Command: Practical Text‑Manipulation Examples

Basic Character Replacement

The most common use of tr is to replace characters. For example, replacing all lowercase "o" with the digit "0": echo "Hello, World!" | tr 'o' '0' Output:

Hell0, W0rld!

Delete Characters

Use the -d option to delete specific characters, such as all vowels: echo "Remove all vowels" | tr -d 'aeiou' Output:

Rmv ll vwls

Character Set Conversion

Case Conversion

Convert uppercase to lowercase or vice‑versa:

echo "Convert To Lowercase" | tr 'A-Z' 'a-z'
echo "Convert To Uppercase" | tr 'a-z' 'A-Z'

Outputs: convert to lowercase and

CONVERT TO UPPERCASE

Translate Character Sets

Map one set of characters to another using the -t option: echo "12345" | tr -t '123' 'abc' Output:

abc45

Deduplication and Whitespace Compression

Remove Duplicate Characters

Compress consecutive spaces into a single space with -s: echo "Hello, World!" | tr -s ' ' Output:

Hello, World!

Delete All Whitespace

Delete every space character using -d: echo "Remove extra spaces" | tr -d ' ' Output:

Removeextraspaces

Escaping Special Characters

Escape Newlines

Replace newline characters with commas: echo "Line1\nLine2" | tr '\n' ',' Output:

Line1,Line2

Escape Tabs

Replace tab characters with a hyphen: echo "Tab1\tTab2" | tr '\t' '-' Output:

Tab1-Tab2

Character Ranges and Multi‑Character Replacement

Range Replacement

Replace a range of characters, e.g., ‘a‑c’ with ‘x’: echo "abcdef" | tr 'a-c' 'x' Output:

xxxdef

Multi‑Character Replacement

Map multiple source characters to multiple target characters: echo "apple" | tr 'ae' '123' Output:

1ppl2

Reading Character Sets from Files

Use -s together with -f to read a character set from a file, useful for large sets: echo "abcde" | tr -s -d -f char_set.txt Here char_set.txt contains the characters to delete, and -f tells tr to read the set from that file.

Summary

The Linux tr utility is a versatile tool for text processing, capable of character replacement, deletion, case conversion, whitespace handling, special‑character escaping, and reading sets from files, making it essential for scripting and data transformation tasks.