Disk Related Commands
# 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
Security Related Commands
# 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
Network Related Commands
# Find the NIC speed
$ mii-tool
File/Dir Commands
# 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 \;
MySQL Hacker