How to use grep Command in linux

This article uses easy-to-understand examples to introduce the use of grep commands in linux, the code is very detailed, interested friends can refer to, hope to be helpful.

Grep

Grep is a powerful text search tool that uses regular expressions to search for text and print matching lines.

Common syntax:

[root@www ~] # grep [- acinv] [--color=auto] 'search string' filename

Options and parameters:

-a: search binary files for data in the form of text files

-c: calculates the number of times a 'search string' is found

-I: ignore the case difference, so the case is considered the same

-n: output line number

-v: reverse selection, that is, the line that shows no 'search string' content

-- color=auto: you can color the keywords you find.

For example:

Take out the line where root appears in / etc/passwd

# grep root / etc/passwdroot:x:0:0:root:/root:/bin/bashoperator:x:11:0:operator:/root:/sbin/nologin or # cat / etc/passwd | grep root root:x:0:0:root:/root:/bin/bashoperator:x:11:0:operator:/root:/sbin/nologin

Take out the lines where root appears in / etc/passwd and display the line numbers of these lines in / etc/passwd

# grep-n root / etc/passwd1:root:x:0:0:root:/root:/bin/bash30:operator:x:11:0:operator:/root:/sbin/nologin this is the end of the usage of the grep command in linux. I hope the above content can be of some help and learn more. If you think the article is good, you can share it for more people to see.