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