 
mount - mount a filesystem
$ mount
# mount -a
# mount <source> <target> [-t fstype] [-o options]If invoked without any arguments, mount prints a list of all currently mounted filesystems.
If invoked as mount -a, mount mounts all the filesystems configured in /etc/fstab and /etc/fstab.d/*. This is normally done on system startup by SystemServer(7).
Otherwise, mount performs a single filesystem mount. Source should be a path to a file containing the filesystem image. Target and fstype have the same meaning as in the mount(2) syscall (if not specified, fstype defaults to ext2).
A special source value "none" is recognized, in which case mount(8) will not attempt to open the source as a file, and will pass an invalid file descriptor to mount(2). This is useful for mounting pseudo filesystems.
Options correspond to the mount flags, and should be specified as a comma-separated list of flag names (lowercase and without the MS_ prefix). Additionally, the name defaults is accepted and ignored.
/etc/fstab - read by mount -a on startup to find out which filesystems to mount./etc/fstab.d - directory with drop-in additions to the normal fstab file, also read by mount -a./sys/kernel/df - read by mount to get information about mounted filesystems.# mount devpts /dev/pts -t devpts -o noexec,nosuid
# mount /home/anon/myfile.txt /tmp/foo -o bind
# mount a regular file using a temporary loop device
$ mount /home/anon/myfilesystem.bin /mnt