Top 10 SED Use Cases Every Linux User Should Know

The Stream Editor (sed) is one of the most powerful text-processing tools in Unix and Linux. With sed, you can automate text transformations and streamline tasks, from simple substitutions to complex multi-line edits. Here, we’ll explore the top 10 sed use cases, with practical examples to help you work efficiently from the command line.

1. Basic Text Substitution

A common use of sed is replacing text in files. You can change all occurrences of a word, phrase, or pattern with another—useful for tasks like renaming terms in documents or code.

Example: Replace all occurrences of “cat” with “dog” in pets.txt.

sed 's/cat/dog/g' pets.txt

In this command:

• s denotes the substitution.
• cat is the text to replace.
• dog is the new text.
• g ensures all occurrences on each line are replaced. Without it, only the first instance on each line changes.

Why it’s useful: Simple substitutions are essential for text file automation, especially when replacing repetitive terms across long documents or scripts.

2. Replace Text Only on Specific Lines