Awk

awk is a command for string operations. For example, it allows you to show only the second column of a file. awk and gawk (for GNU awk) are used synonymously.

Examples

Show only the second column of file.txt

awk '{print $2;}' file.txt

kill all processes of a user

ps --no-header -fu <username> | awk '{ print $2 }' | grep -v $$ | xargs kill

extract eth0's MAC address from ifconfig output

ifconfig | grep eth0 | awk '{ print $5 }'

See also

• gawk man page
• piping
• Shell Scripting Tutorial