Erstes Wort
grep -Eo '^[^ ]+'
Letztes Wort
grep -oE '[^ ]+$'
extract IP addresses
grep -oE '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}'|
exclude lines which begin with "#" or ";"
grep "^[^#;]"
exclude empty lines and contain #
egrep -v '#|^$'
exclude lines which contain with "//"
grep -v "//"
exclude lines which are empty
grep -ve '^$'
phrase
grep "Host not found" /var/log/mail.*
➜ ~ alias G "G"G='| grep'