[SOLVED] [BASH] grep IP address and IP with network mask in one go?

czezz · 05-29-2024, 07:22 AM

Initial file:

Code:

cat file.txt 
172.16.100.0/24
148.180.112.67

Following grep will extract IP address only from file.txt

Code:

cat file.txt | grep -o '[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}'
172.16.100.0
148.180.112.67

Following grep will extract IP with its netmask only (will skip any IP addresses without \netmask)

Code:

cat file.txt | grep -o '[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\/[0-9][0-9]'
172.16.100.0/24

I was trying to combine both adding -E flag but that wont work:

Code:

cat file.txt | grep -o -E "'[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}'|'[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\/[0-9][0-9]'"

Ofc, i can run it in 2 steps and then process/merge outputs.
However, i was wondering if anyone knows some clever way to have it all in one go?

czezz · 05-29-2024, 07:28 AM

Ah, i think i sorted it out. I was close

Code:

cat file.txt | grep  -E ''[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}'|'[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\/[0-9][0-9]''

boughtonp · 05-29-2024, 07:37 AM

Code:

grep -oP '\b[\d.]{7,15}(/\d{1,2})?\b' file.txt

Then validate the output, accordingly.

pan64 · 05-29-2024, 07:41 AM

Do you mean this?

Code:

grep -E 'regex1|regex2' file.txt

https://unix.stackexchange.com/quest...-regex-problem

syg00 · 05-29-2024, 07:54 AM

Ah, I love the resurrection of an old chestnut like parsing IP addresses.

Nuthin' new in the (*nix) universe ...

MadeInGermany · 05-30-2024, 11:12 AM

Code:

grep -Eo '[0-9]{1,3}(\.[0-9]{1,3}){3}(/[0-9]{1,2})?' file.txt

With bash-builtins:

Code:

while read x; do [[ $x =~ [0-9]{1,3}(\.[0-9]{1,3}){3}(/[0-9]{1,2})? ]] && echo "$BASH_REMATCH"; done < file.txt