what type does shutdown use to store seconds?
 

I want to shutdown the pc in 12-13 hours, so we're talking about 43800 seconds. Does shutdown use an int or a short int? I wouldn't want an overflow :)

Also, I remember reading about a command giving the first 10 lines from long lines of input. Can someone tell me which one was? Thanks

The shutdown command uses minutes, not seconds, so you should be safe from overflows either way.

With the shutdown command, you can either specify the time as HH:MM (giving the clock time, not the length of time to wait), or as +690 to mean “wait 690 minutes from now”

The other command you're looking for is probably head, although it defaults to 20 lines. will do the job. There's also a similar tail command that outputs the last lines.

Thanks, I hastilly looked at the man page, saw the -t sec option and thought, hmm, it's in seconds. I think I had read about tail, but head will do just as well. Thanks a lot :)

The -t option is given to init, which can be used for an additional wait. Basically this can be used to give you shutdown resolution down to a second if you need it. e.g.:
This will start shutting down at two seconds past one minute past midnight.