freeCodeCamp/guide/english/bash/bash-grep/index.md

title
Bash Grep

Bash command: grep

grep stands for Global Regular Expression Print. It is used to search piped input or files for a string which can contain regex.

Usage

grep <some string> <file name>

Commonly used options:

• -i - Ignores the case when performing the search.
• -v - Inverts the search and only selects lines that do not match the search string.

Examples

Search for IP 127.0.0.1 in the /etc/hosts file

grep "127.0.0.1" /etc/hosts

Search for oom (out of memory) in /var/log/messages

grep -i oom /var/log/messages

More Information

• run man grep for a full list of available flags/options to use.
• Wikipedia