Make sure a script is run in a terminal.

[ -t 0 ] || exit 1
Exit with error if script is not run in a terminal

21
2009-11-20 23:14:49

2 Alternatives + Submit Alt

  • Oddly, the isatty(3) glibc C call doesn't have a direct analogue as a command 'isatty(1)'. All is not lost as you can use test(1). For example, your script might be run from a tty or from a GUI menu item but it needs to get user-input or give feedback. Now your script can test STDIN with 'isatty 0' or STDOUT with 'isatty 1' and use xmessage(1) if the tty is not available. The other way to test for this is with 'tty -s' - but that's only for STDIN.


    3
    isatty(){ test -t $1; }
    bhepple · 2010-01-06 06:50:01 0
  • If your script needs to be run in a terminal, this line at the top will stop it running if you absent-mindedly double-click the icon, perhaps intending to edit it. (Of course this won't help with scripts that run in the background.)


    0
    tty > /dev/null 2>&1 || { aplay error.wav ; exit 1 ;}
    johnraff · 2009-11-04 16:18:00 3

What Others Think

Very nice. You ought to explain how it works, though.
flatcap · 609 weeks and 5 days ago
man test
cfajohnson · 609 weeks and 5 days ago
Even when you're not on a TTY, one should still write to stderr before dying. Some interactive sessions don't show up as TTYs and it'd be best if your script didn't fail silently.
hackerb9 · 609 weeks and 3 days ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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