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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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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!

Top Tags



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

Check a server is up. If it isn't mail me.

Terminal - Check a server is up. If it isn't mail me.
nc -zw2 www.example.com 80 || echo http service is down | mail -s 'http is down' [email protected]
2010-09-08 13:18:16
User: putnamhill
Functions: echo mail
Check a server is up. If it isn't mail me.

This version uses netcat to check a particular service.


There are 2 alternatives - vote for the best!

Terminal - Alternatives
ping -q -c1 -w3 brandx.jp.sme 2&>1 /dev/null || echo brandx.jp.sme ping failed | mail -ne -s'Server unavailable' [email protected]
2009-10-13 14:13:04
User: mccalni
Functions: echo mail ping
Tags: bash ping mail

Joker wants an email if the Brand X server is down. Set a cron job for every 5 mins with this line and he gets an email when/if a ping takes longer than 3 seconds.

curl -fs brandx.jp.sme 2&>1 > /dev/null || echo brandx.jp.sme ping failed | mail -ne -s'Server unavailable' [email protected]
2009-10-23 14:29:06
User: mccalni
Functions: echo mail ping
Tags: bash ping curl mail

Alternative to the ping check if your firewall blocks ping. Uses curl to get the landing page silently, or fail with an error code. You can probably do this with wget as well.

ping -q -c1 -w3 server.example.com >& /dev/null || echo server.example.com ping failed | mail -ne -s'Server unavailable' [email protected]
2010-09-08 12:19:29
User: brainstorm
Functions: echo mail ping
Tags: bash ping mail

For some reason the 2&>1 does not work for me, but the shorter stdout/stderr redirection >& works perfectly (Ubuntu 10.04).

Know a better way?

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