Looping in the shell… “for” is your friend.

Why repeat the same command 10 times when you can put it in a loop??

Put “for” to use… Here are a few examples:

* Kill off all processes for a specific application..

for PID in  `ps -ef | grep app_name | grep -v grep | awk '{print $2}'`
do
  kill -9 ${PID}
done

* Lock out out all the users in a specific group…

GROUP=`grep group_id /etc/group | awk -F":" '{print $3}'`
for USER in `grep ":${GROUP}:" /etc/passwd | awk -F":" '{print $1}'`
do
  passwd -l ${USER}
done

* Untar a bunch of files…

gunzip *.tar.gz
for TARBALL in `ls -1 *.tar`
do
  tar xf ${TARBALL}
done

I could go on…