grep -Eoa "\b(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\b" Filetosearch.txt

Regex to reliably search a file for valid IP addresses (and external IP addresses)

Command returns valid IP addresses. Append the following regex to additionally filter out NAT and reserved IP addresses | grep -Ev "^0|\.0[0-9]|^10\.|^127\.|^169\.|^172\.(1[6-9]|2[0-9]|3[01])|^192.168.|^2(2[4-9]|3[0-9])|^2(4[0-9]|5[0-5])"

0
By: jsbrown
2014-11-02 19:50:54

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What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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