lsof is magical

Here is a link, which is kind of primer for lsof, since it has examples.

Here are some examples I have come across which are interesting and cool.

kill -9 `lsof -t -c sshd +f -- /dev/md2`
I want to kill all process which connects to my sshd, and are accessing raid /dev/md2. ensures no one is connected via ssh and is using the drive. I can then safely shut down sshd.


lsof -t -c java -a -u -a +f -- /dev/md2
this is a combination of
-c command
-a and
-u userid
-a and (another and)
+f file accessing raid disk.


lsof +f -- /var/log
everything accessing

you send a HUP to all process accessing /var/log, generally daemons accessing logs
kill -HUP `lsof +f -- /var/log`


lsof -i| grep LISTEN
all that your host is listening (-i is for tcp connections)

who is connected on port 6014
lsof -i:6014

lsof -i:22 -a -u
all those connected to port 22 and having remember if you do not specify -a, it becomes an or and that would mean any thing accessed by

# lsof -i:22 -a -u *uid* | wc -l
14

# lsof -i:22 -u *uid* | wc -l
1228

remeber -t is for terse, it understands, that you only are interested in the process id.

# lsof -t -i:22 -u *uid* | wc -l
100

even thoud *uid* user was accessing tons of files etc. he is running 100 process which are the handles to all those activity.

enjoy!