Подскажите по grep

sed 's/192.131.166.1, //' fileip.txt

cat fileip.txt | grep -E -o "([0-9]{1,3}[\.]){3}[0-9]{1,3}" | grep -v "192.131.166.1$"

[/tmp] $ cat fileip.txt
192.131.166.15, 192.131.166.1, 192.131.166.8, 192.131.166.12
[/tmp] $ sed 's/192.131.166.1, //' fileip.txt
192.131.166.15, 192.131.166.8, 192.131.166.12

sed 's/192.131.166.1, //;s/\, /\n/g' fileip.txt