Whenever you mount or unmount a file system, the /etc/mnttab (mount table) file is modified with the list of currently mounted file systems. You can display the contents of this file with the cat or more commands, but you cannot edit it. Here is an example of an /etc/mnttab file:
$ more /etc/mnttab /dev/dsk/c0t0d0s0 / ufs rw,intr,largefiles,onerror=panic,suid,dev=2200000 938557523 /proc /proc proc dev=3180000 938557522 fd /dev/fd fd rw,suid,dev=3240000 938557524 mnttab /etc/mnttab mntfs dev=3340000 938557526 swap /var/run tmpfs dev=1 938557526 swap /tmp tmpfs dev=2 938557529 /dev/dsk/c0t0d0s7 /export/home ufs rw,intr,largefiles,onerror=panic,suid,dev=2200007 ... $ |