Viewing /proc/mounts

The /proc/mounts file is part of the proc virtual file system. As with the other files under /proc/, the mounts "file" does not exist on any disk drive in your Red Hat Enterprise Linux system.
In fact, it is not even a file; instead it is a representation of system status made available (by the Linux kernel) in file form.
Using the command cat /proc/mounts, we can view the status of all mounted file systems:
 rootfs / rootfs rw 0 0 /dev/root / ext3 rw 0 0 /proc /proc proc rw 0 0 usbdevfs /proc/bus/usb usbdevfs rw 0 0 /dev/sda1 /boot ext3 rw 0 0 none /dev/pts devpts rw 0 0 /dev/sda4 /home ext3 rw 0 0 none /dev/shm tmpfs rw 0 0 none /proc/sys/fs/binfmt_misc binfmt_misc rw 0 0 
As we can see from the above example, the format of /proc/mounts is very similar to that of /etc/mtab. There are a number of file systems mounted that have nothing to do with disk drives. Among these are the /proc/ file system itself (along with two other file systems mounted under /proc/), pseudo-ttys, and shared memory.
While the format is admittedly not very user-friendly, looking at /proc/mounts is the best way to be 100% sure of seeing what is mounted on your Red Hat Enterprise Linux system, as the kernel is providing this information. Other methods can, under rare circumstances, be inaccurate.
However, most of the time you will likely use a command with more easily-read (and useful) output. The next section describes that command.