LINUX: How to Remove/Ignore/Not Display Blank Lines in A File Using grep command

Below grep command can be used for removing/ignoring and not displaying blank lines in a file.

grep -v -e '^$'  <filename>

Products to which Article Applies

All Linux Operating Systems

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LINUX: GREP Command To Extract IP Addresses From Command Output Or File (How To Doc)

Below grep command can be used to extract IP addresses from a file.

grep -o '[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}' <filename>

To extract IP addresses from command output below grep command can be used.

<command> | grep -o '[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}'

For example, below is grep command to extract IP addresses from "ip addr" command output.

ip addr | grep -o '[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}'

Below is sample output of above command.

10.10.10.137
10.20.11.12

Products to which Article Applies

All Linux Operating Systems

Additional Reference

https://www.shellhacks.com/regex-find-ip-addresses-file-grep/

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