Get access to an entire filesystem in one directory. More information: https://manned.org/mount.8.
mount
mount -t filesystem_type path/to/device_file path/to/target_directory
mount --mkdir path/to/device_file path/to/target_directory
mount -o uid=user_id,gid=group_id path/to/device_file path/to/target_directory
/cdrom
(readonly):mount -t iso9660 -o ro /dev/cdrom /cdrom
/etc/fstab
:mount -a
/etc/fstab
(e.g. /dev/sda1 /my_drive ext2 defaults 0 2
):mount /my_drive
mount --bind path/to/old_dir path/to/new_dir