Occasionally Ubuntu runs a file check, and I assume repair if necessary, at start-up. what do I type into Terminal if I want to run a file check without waiting for the automatic file check to start?
The reason I ask is that my system wouldn't boot last week and after several attempts to reboot, the automatic file check came into play and corrected whatever was wrong. This process of rebooting my system several times before Ubuntu fixed itself was very time consuming and frustrating. I dare say that there is a command line to trigger this file check and I would appreciate it if someone with greater knowledge than I could supply it.

Thank you.

Hi,

Take a look at
fsck
http://linux.die.net/man/8/fsck

Kind regards

Be aware that you can't (as in shouldn't) run fsck against a mounted filesystem. It'll maybe/probably be o.k., but you'll never know, and never be able to prove it.
Especially the root, as likely is your issue - you can generally force a fsck at the next boot by using "shutdown -F" (as root). Depends on distro, but I'd be pretty confident Ubuntu support it.

You can run this anytime:

Whenever you want to reboot, this command will force a filesystem check during reboot.