User and Group

/etc/passwd
username:password:uid:gid:gecos(사용자추가정보):homedir:shell

/etc/group
groupname:password:gid:members(구분은 , 로)

mount
mount -t type(file_system_type) device(물리적 장치) mount_point(mount시킬 directory)
ex)
mount -t ext2 /dev/hda2 /mnt
moutn -t iso9660 -r(or -ro) /dev/cdrom /mnt

부팅시 auto_mount는 /etc/fstab에 기록
※umount device(or mount_point)