Usefull Centos Command Line for Die Hard System Administrator

Find disk usage by partition in a human readable format.

df -h

Find the top 100 space eating monster file/dir under a directory.

du -a [dir] | sort -n | tail -100

Find out what files a logged in user has opened (ignoring libs, devices, sockets, pipes)

lsof | grep [username] | egrep -v '(lib|/dev|pipe)'

Find which process is connected to what port and which remote host.

netstat -pat

Find the NIC speed.

mii-tool

Move all files with specific pattern to a sub-directory which might already have files with same pattern ..

find . -maxdepth 1 -name "*2008*.txt" -exec mv {} 2008 \;