Master Linux Text Processing with grep, sed, and awk

In Linux, text processing involves viewing and modifying file contents. While editors like Vim allow interactive editing, many scenarios require automated handling using command‑line utilities.

grep – pattern search

The grep command searches one or more files for lines that match a given regular expression, which can be a single character, string, word, or sentence.

sed – stream editor

The sed utility processes text according to a script of commands supplied on the command line or stored in a file. It reads input line by line, applies the specified rules, modifies data in a buffer (leaving the original file unchanged unless the -i option is used), and outputs the result.

Read one line at a time.

Match and modify data according to the provided commands.

Write the processed line to the output.

After a line is processed, sed proceeds to the next line and repeats this cycle until the entire file has been handled.

awk – pattern‑action language

The awk command also scans a file line by line, looking for lines that contain a target pattern. When a line matches, the user‑defined actions are executed on that line; otherwise the line is left unchanged.