Wow, this is crazy. Here it is

Kyle and I are going to be starting a podcast in the near future called Cit3.

We’ll be talking about anything related to the previous week.

More about this later,
Jon Howe

This week’s command is: alias

This command is great. In short it allows you to create Pseudo commands.

For example, on the server that this site runs on (my server), I regularly need to check to see what connections my computer has initiated, and what services they’re through. I do this using the linux command netstat using the following command line string: “netstat -pan | grep tcp“. Since I’m not doing this blog on netstat I will not explain that to you. If you have any questions, just comment on this post below and either me(Jon) or Kyle will attempt to explain it to you.

Now isn’t that command a little bit cumbersome? I think so at least. This is where alias comes in handy.

To set up an alias in your *nix based profile do the following things:

1. Login as your user
2. Type in cd ~
3. Edit your .bashrc file using the text editor of your choice. I’ll be using vi, so I’ll type in vi .bashrc
4. You create an alias using the following syntax: alias NEW_COMMAND=”COMMAND STRING_TO BE EXECUTED”
5. Using the example above you would type in the following: alias ns=”netstat -pan | grep tcp”

So now anytime that you enter “ns”, “netstat -pan | grep tcp” will be executed in it’s place.

I should mention that you don’t have to place the alias command in your .bashrc file. You can also run it on the commnad line, but it will only have its effect for the current session.

Hopefully this’ll help you out at some point.

More later,
Jon Howe

Alright, I told you that I’d be posting another quickie on screen so here it is.

There’s not much more to talk about that’s relevant, except for one piece.

Restoring from saved sessions:
In order to view the saved sessions enter screen -r. you should be presented with a list of available sessions.
To restore a session enter the following command: screen -r SESSION_NAME.

That’s pretty much all that you need to know.

More tomorrow,
Jon Howe

This week’s command is: screen

I actually just found this command recently. It’s a great little treasure that expands the use of unix in a huge way. Let me explain.

For those of you who don’t know, Unix uses a CLI (or Command Line Interface), meaning that there are no “windows” or “X” boxes to close the windows, it’s all handeled by the keyboard and text on the screen.

Multitasking is critical with computers, and until recently, I’ve been cheating by opening up separate windows in my SSH (or Secure Shell) client. This can be a little bit tiring because you have to connect to the server each time you make a new window.

Screen takes care of this completely by allowing you to have multiple of what I like to call “virtual sessions”. Now an example.

So you connect to your server and want to have one of these so-called “virtual sessions”. It’s easy. Just get to the command line and enter screen.

Your screen should go blank, Congrats! Your in a virtual session.

In order for you to go back to your original session hit ctrl + a and then d.

This closes your virtual session, but keeps it open in memory. If you want to close it completely, just hit ctrl + a and then hit shift + d, or uppercase D.

Either of these two will bring you back to your original screen and will either keep the contents intact or destroy them.

Now that you’re back at your original screen just hit screen -s to restore your session! It’s as easy as that.

Maybe I’ll add some more advanced features of screen later this week, and give ya a freebie.

More later,
Jon Howe