Mounting a RAM drive
$ mount -t tmpfs -o size=5G,nr_inodes=5k,mode=700 tmpfs /tmp
Visudo
sudo visudo
username ALL=(ALL) NOPASSWD:/sbin/restart whatever
Display the amount of available disk space
df
df -h # human-readable format
df -a # all filesystems
Display disk usage
du
du -hsx * | sort -rh | head -10 # largest 10 folders
Answer yes in a bash script
yes | /your/command