Linux Blog

Shell Script Flow Control – my most refered to articles

Filed under: Shell Script Sundays — TheLinuxBlog.com at 2:38 pm on Sunday, November 9, 2008

This week I do not have time to write a full fledged article on shell scripting, so I am going to some flow control and logic articles that I wrote that I read the most.

One script that I continuously refer to is one of the first shell scripting articles I wrote titled “When Photoshop Fails.” The reason I refer to this article is because it describes a couple of looping techniques and a loop that works with spaces in filenames. For those interested but do not want to read the whole thing here is the loop in short:

find * -iname “*” | while read i; do echo “$i”; done

The next article I’m linking to is the one I wrote on loops: http://www.thelinuxblog.com/for-while-and-until-loops-in-bash/ it outlines some of the basic looping techniques. What I fail to mention in this article is that seq can be used to generate sequences of numbers for the [in list] section. The following is how you would create a loop to loop from 1 to 10 echoing out each number:

for i in `seq 1 10`; do echo $i; done;

Select Statements in Bash is exactly what the title implies. How to implement select statements in bash scripting. Also known as switch’s and case’s in other languages many will be familiar with this sort of logic. Even though I do not refer to it as often as some of the other articles I think it is worth of a mention in this list.

Decision making using if statements is something that every shell scripter is bound to come across. While not exactly the most in depth article on bash if then else statements it is a good start for any one wanting to learn more.

I love dialog’s and it just so happens that dialog and xdialog do a great job of making dialogs for your shell scripts. Creating Dialogs with Dialog has some basic uses of dialog. While it is not exactly logic or flow control, it can be used to prompt the user for input or just to pretty things up a little. It just so happens that it has an X front end called xdialog which does a good job too.

This is not all of the articles I refer to, but its the ones I wrote. If any one else has a list of articles they refer to that are bookmarked that I wrote or not I’d be interested to see them. Just paste them in a comment.

Reworking Shell Scripts – Part 2

Filed under: Shell Script Sundays — TheLinuxBlog.com at 10:00 pm on Sunday, September 14, 2008

In the last Shell Script Sunday’s article I wrote, I said that I’d show you some more ways to rework shell scripts to make them easier to use. I’ve got some more tricks up my sleeve that I’d like to share, itsĀ  been rather busy this site of the internet at TheLinuxBlog.com. So why I write up some more shell scripting methods, here are some previous posts that can enhance your shell scripts. Be sure to comment on them if you find them useful, or would like more information.

Creating Dialogs with Dialog
If you have a shell script that you use on a regular basis, you may want to consider using dialog to make it more user friendly. Dialog makes it easy to create easy to use dialogs that are intuitive and easy to use. There are so many combinations of dialogs that can be created that the possibilities are ended. Dynamically create dialogs for select lists, input boxes, progress bars and much much more.

Graphical Shell Scripting
This article I wrote introduces graphical shell scripting. Similar to dialog this is an updated “Dialog” and works within X. If you support end users, or your target audience is Ubuntu/Linspire users (j/k) then XDialog may be the better choice. Its got most of the same functionality as Dialog except it depends on X. You can even support both Dialog and XDialog as they pretty much use the same syntax.

Graphical Shell Scripting

Filed under: Shell Script Sundays — TheLinuxBlog.com at 4:07 pm on Sunday, December 16, 2007

From all of my other previous shell scripting articles you can see that shell scripting is a very good way to get a task done or to automate. This is great but some times a little bit of that three letter acronym “GUI” is a nice touch. Well my friends, if you’ve been reading my articles and following my dialog examples then you are in luck. If not don’t worry, you can view all of the articles in the Shell Script section to the right.

The program to make your GUI’s for your shell scripts is the exact same thing as dialog except its graphical. Its called Xdialog. Once installed you basically use it the same way as dialog. If your thinking about upgrading a script thats written in dialog you might want to think twice because some window managers will display the windows differently.

Check out these Xdialog examples and corresponding screenshots:

Xdialog

Xdialog -yesno “Do you like Xdialog?” 5 50 && echo “Thats nice” || echo “Yea, some times its better to stick to CLI”

Xdialog ExampleXdialog Example