mtab(5)
NAME
mtab − mounted file system table
DESCRIPTION
The /etc/mtab file contains a table of devices mounted by the mount command. The umount command removes entries.
Each entry is 64 bytes long. The first 32 are the null-padded name of the place where the special file is mounted. The second 32 are the null-padded name of the special file. The special file has all its directories stripped away. That is, everything through the last “/” is thrown away.
This table is present only so people can look at it. It does not matter to mount if there are duplicated entries nor to umount if a name cannot be found.
FILES
/etc/mtab