mtab
also: mount table
A system file at /etc/mtab that records currently mounted filesystems and their mount options. It provides a dynamic view of what is actually mounted on the system.
/etc/mtab (mount table) is a file maintained by the mount and umount commands to track which filesystems are currently mounted on your system. Each line represents one mounted filesystem with details like the device, mount point, filesystem type, and mount options.
On modern systems, mtab is often a symbolic link to /proc/mounts, which is generated dynamically by the kernel. This ensures the file always reflects the true state of mounted filesystems, even if mtab becomes out of sync.
You can view currently mounted filesystems by reading /etc/mtab or running mount with no arguments. For example, a line might look like: /dev/sda1 / ext4 rw,relatime 0 0, indicating partition sda1 is mounted at root as ext4 with read-write access.