detect already mounted filesystems. The kernel
           table with already mounted filesystems is cached during mount --all.
           This means that all duplicated fstab entries will be mounted.

           The correct functionality depends on /proc (to detect already
           mounted filesystems) and on /sys (to evaluate filesystem tags like
           UUID= or LABEL=). It’s strongly recommended to mount /proc and /sys
           filesystems before mount -a is executed, or keep /proc and /sys at
           the beginning of fstab.

           The option --all is possible to use for remount operation too. In
           this case all filters (-t and -O) are applied to the table of
           already mounted filesystems.

           Since version 2.35 it is possible to use the command line option -o
           to alter mount options from fstab (see also --options-mode).

           Note that it is a bad practice to use mount -a for fstab checking.
           The recommended solution is findmnt --verify.

       -B, --bind
           Remount a subtree somewhere else (so that its contents are available
           in both places). See above, under Bind mount operation.

       -c, --no-canonicalize
           Don’t canonicalize paths. The mount command canonicalizes all paths
           (from the command line or fstab) by default. This option can be used
           together with the -f flag for already canonicalized absolute paths.
           The option is designed for mount helpers which call mount -i. It is
           strongly recommended to not use this command-line option for normal
           mount operations.

           Note that mount does not pass this option to the /sbin/mount.type
           helpers.

       -F, --fork
           (Used in conjunction with -a.) Fork off a new incarnation of mount
           for each device. This will do the mounts on different devices or
           different NFS servers in parallel. This has the advantage that it is
           faster; also NFS timeouts proceed in parallel. A disadvantage is
           that the order of the mount operations is undefined. Thus, you
           cannot use this option if you want to mount both /usr and
           /usr/spool.

       -f, --fake
           Causes everything to be done except for the actual system call; if
           it’s not obvious, this "fakes" mounting the filesystem. This option
           is useful in conjunction with the -v flag to determine what the
           mount command is trying to do. It can also be used to add entries
           for devices that were mounted earlier with the -n option. The -f
           option checks for an existing record in /etc/mtab and fails when the
           record already exists (with a regular non-fake mount, this check is
           done by the kernel).

       -i, --internal-only
           Don’t call the /sbin/mount.filesystem helper even if it exists.

       -L, --label label
           Mount the partition that has the specified label.

       -l, --show-labels
           Add the labels in the mount output. mount must have permission to
           read the disk device (e.g. be set-user-ID root) for this to work.
           One can set such a label for ext2, ext3 or ext4 using the e2label(8)
           utility, or for XFS using xfs_admin(8), or for reiserfs using
           reiserfstune(8).

       -M, --move
           Move a subtree to some other place. See above, the subsection The
           move operation.

       -m, --mkdir[=mode]
           Allow to make a target directory (mountpoint) if it does not exist
           yet. Alias to "-o X-mount.mkdir[=mode]", the default mode is 0755.
           For more details see X-mount.mkdir below.

       -n, --no-mtab
           Mount without writing in /etc/mtab. This is necessary for example
           when /etc is on a read-only filesystem.

       -N, --namespace ns
           Perform the mount operation in the mount namespace specified by ns.