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commandlinefu.com is the place to record those command-line gems that you return to again and again.

Delete that bloated snippets file you've been using and share your personal repository with the world. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.


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Universal configuration monitoring and system of record for IT.
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May 19, 2015 - A Look At The New Commandlinefu
I've put together a short writeup on what kind of newness you can expect from the next iteration of clfu. Check it out here.
March 2, 2015 - New Management
I'm Jon, I'll be maintaining and improving clfu. Thanks to David for building such a great resource!
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Psst. Open beta.

Wow, didn't really expect you to read this far down. The latest iteration of the site is in open beta. It's a gentle open beta-- not in prime-time just yet. It's being hosted over at UpGuard (link) and you are more than welcome to give it a shot. Couple things:

  • » The open beta is running a copy of the database that will not carry over to the final version. Don't post anything you don't mind losing.
  • » If you wish to use your user account, you will probably need to reset your password.
Your feedback is appreciated via the form on the beta page. Thanks! -Jon & CLFU Team

Is it a terminal?

Terminal - Is it a terminal?
isatty(){ test -t $1; }
2010-01-06 06:50:01
User: bhepple
Functions: test
3
Is it a terminal?

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.

Alternatives

There are 2 alternatives - vote for the best!

Terminal - Alternatives
[ -t 0 ] || exit 1
2009-11-20 23:14:49
User: cfajohnson
Functions: exit
Tags: shell script
21

Exit with error if script is not run in a terminal

tty > /dev/null 2>&1 || { aplay error.wav ; exit 1 ;}
2009-11-04 16:18:00
User: johnraff
Functions: aplay exit tty
Tags: shell script
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.)

Know a better way?

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