A few Terminal tips

A couple of days ago I found an interesting article called Lazy Linux: 10 essential tricks for admins, so I decided to try a couple of these on my Mac – I’m running Tiger, by the way.

1. Unmounting a stuck DVD (or disk image, for that matter)

I could not find the fuser command mentioned for linux on my Mac but we can always use lsof.

If you’re trying to eject a disk called Movies and are getting the old The disk “Movies” is in use and could not be ejected message you can open up the Terminal and run the following commands to find which app is at fault:

$ lsof | grep Movies

You should get something like this:

QuickTime 404  myuser  13r   REG   14,3 735825920   45186 /Volumes/Movies/My Movie.mov

This example tells you that QuickTime has a file called My Movie.mov open from the Movies disk. So just close the file in QuickTime and you should be able to eject your DVD/image file.

2. Collaboration with screen

This one worked exactly as it says in the article. Just do the following:

  • Open up the Terminal on your Mac. Let’s assume your username is myuser.
  • From another machine, open up an SSH connection to your Mac as myuser.
  • From the remote machine type the following:
  • $ screen -S myscreen 
  • Now, from the Mac Terminal type the following:
  • $ screen -x myscreen
  • Your Mac Terminal session and your SSH session should now be joined together. Anything you do on the Mac will be seen from the remote machine and viceversa. This is great for collaboration or troubleshooting.
  • To exit myscreen just type exit from either machine.


The linux article includes tips for:

  1. Unmounting the unresponsive DVD drive – works great.
  2. Getting your screen back when it is hosed.
  3. Collaboration with screen – I did not know about this, works great.
  4. Getting back the root password – I will probably try this one soon.
  5. SSH back door.
  6. Remote VNC session through an SSH tunnel.
  7. Checking your bandwidth.
  8. Command-line scripting and utilities.
  9. Spying on the console.
  10. Random system information collection.

So if you’re a linux user check them out. They could come in handy eventually.


Developing iPhone applications using Ruby on Rails and Eclipse

I just found these articles over at IBM’s developerWorks website on developing webapps for the iPhone using Rails and Eclipse:

  1. Developing iPhone applications using Ruby on Rails and Eclipse, Part 1: Serving content for iPhones.
  2. Developing iPhone applications using Ruby on Rails and Eclipse, Part 2: Displaying iPhone content to the client.
  3. Developing iPhone applications using Ruby on Rails and Eclipse, Part 3: Developing advanced views for iPhone.

They look pretty interesting. I will probably check them out as soon as I have some spare time.

You can also check these out:


100 Push ups

Are you one of those people who, like me, isn’t getting enough exercise?

Would you like to do something about it?

The one hundred push up program is a very simple, very detailed 6-level program to help you get stronger, regardless of your current fitness level – even if you have the strength of Monty Burns.

The idea seems simple enough. You work out three days per week – for a total of approximately 30 minutes – increasing the amount of push ups required to advance to the next level as you make progress. If you can’t complete a level you can always do it over.

So check it out. I think I’m gonna give it a shot.

Dile Nel a Telcel

Hoy fué el gran lanzamiento a nivel mundial del nuevo iPhone 3G de Apple. Y en México, Telcel reveló recientemente los planes y sus costos.

Estos costos sin duda son bastante elevados en comparación con otros países. Puede consultar los precios en otros países en esta liga.

Ahora, debido al abuso de Telcel, se ha iniciado un movimiento al cuál estan invitados a unirse todos los mexicanos para exigir que la compañía de telecomunicaciones reduzca estos costos tan elevados.

Apoya al movimiento Nel Telcel firmando su petición aquí.

Corre la voz. México merece un mejor servicio y mejores precios!

Mail.app in Tiger hangs

So I was trying to check my email and all of a sudden Mail.app was not responding. I had to Force Quit the app because all I was getting was the spinning ball.

I tried again and the same thing happened.

What gives?

So after trying a few different things I decided to disable all my network connections and it finally opened. I just turned Airport back on and Mail.app was working fine again.


By the way, I have Mac OS X 10.4.11.