Linux grep -v: Exclude Lines Tutorial

In Linux, grep -v is a command used for filtering text. It excludes lines containing a specified pattern from the input text and outputs the lines that do not contain that pattern.

Specifically, the meaning of the grep -v command is:

1. Grep is a command used for globally searching a text for lines that match a specific pattern using regular expressions.
2. The -v option indicates inverting the match, meaning it will only output lines that do not match the specified pattern.

For example, suppose there is a file test.txt containing the following content:

apple
banana
cherry
date

If you run the command grep -v “b”, the output will be:

apple
cherry
date

Only the lines that do not contain the letter “b” are kept in the output because the -b option indicates to exclude lines with the letter “b”.