I usually use `mount` to check which filesystems are mounted. I also know there is some connection between `mount` and `/etc/mtab` but I'm not sure about the details. After reading [How to check if /proc/ is mounted](https://unix.stackexchange.com/questions/16154/how-to-check-if-proc-is-mounted) I get more confused.

My question is: How to get the most precise list of mounted filesystems? Should I just use `mount`, or read the contents of `/etc/mtab`, or contents of `/proc/mounts`? What would give the most trustworthy result?