Write a simple launcher using Zenity

Write a simple launcher using Zenity


Nowadays, we mostly interact with our computers using a Graphical User Interface. The operating system as a whole uses several elements of the GUI to make the user experience more human-like. Can users get to unleash some of the GUI's power? The answer is yes: welcome to Zenity, a GTK+ application that works in GNU/Linux, BSD and Windows. In this short article I will show you how to create a simple script that interacts with the user using the GUI.

The problem

Imagine you're changing your computer or your GNU/Linux distribution. All your data files are in your home directory, so you copy them to an external drive. You do the changeover, plug in the external drive, copy your data files into the new home directory, and you're all set to go.

Except for one thing. On the old machine, distro or desktop environment, you had shortcuts to a lot of frequently accessed files, like a household accounts spreadsheet or a favourite piece of music. The shortcuts might have been desktop icons, or a menu list in a launcher, whatever, but they're gone now, and you have to rebuild them.

Or do you? How would you like your shortcuts to be portable, so you could have the same favourites launcher regardless of which Linux distro or which desktop environment you move to?

The solution: Zenity meets xdg-open

The first screenshot shows what you will build in this short article: a favourites launcher written with the wonderful Zenity.

All you need to do is click on a favourite, then either click OK or press Enter on your keyboard. The chosen file will then open in the default program for that file type. That means a spreadsheet will open in your default spreadsheet program, an audio track will open in your default music player, and a website will open in your default browser.

For this handy behaviour we can thank xdg-open, a command line tool. One way Zenity and xdg-open can be combined is shown here.

Copy the code below and paste it into a text editor, save the file as favourites.sh somewhere in your home directory (mine is in a folder called scripts) and make it executable.

#!/bin/bash

file=$(zenity --width=360 --height=320 --list --title "Favourites" --text "Open..." --column File "Current accounts" "2012 Christmas letter" "Flecktones – Cheeseballs in Cowtown" "Free Software Magazine")

if [ "$file" = "Current accounts" ]; then
    xdg-open /home/bob/money/2011-12_accounts.gnumeric

elif [ "$file" = "2012 Christmas letter" ]; then
    xdg-open /home/bob/personal/2012_Xmas_letter.odt

elif [ "$file" = "Flecktones – Cheeseballs in Cowtown" ]; then
    xdg-open /home/bob/music/Fleck/Cheeseballs_in_Cowtown.ogg

elif [ "$file" = "Free Software Magazine" ]; then
    xdg-open http://www.freesoftwaremagazine.com/

else
    exit 0

fi

Use my code as a template to build your own favourites launcher script, by editing the text. Since the script is in your home directory it will go wherever your data files go, and it will be ready for use after a computer, distro or desktop environment change. Just make a quick launcher for the script in its new home (I use a keyboard shortcut, super [Windows key] + z). You can then use the Zenity launcher until you get around to building your preferred file launchers in the new environment.

You might even find (as I did) that a Zenity launcher is really all you need for your shortcuts to often-used files!

How it works

The Zenity dialog with its list of choices is built with the zenity --list command. You can see from the first screenshot where the --title, --text and --column names go. The choices are put in double quotes and are added in the order you want them in the dialog box. You specify the size of the dialog box with the --width and --height options, in pixels.

If you have more choices than will fit the height of the dialog box, Zenity will add a scroll bar at the right of the window. Alternatively, adjust the --height option until you can see all your choices.

The output of the Zenity dialog (the choice you make) should be given a short and simple name so you can use it as a variable in the next command. In this script, I've used the name file for the Zenity output.

The next command is an if A, do this, if B, do that, etc instruction. The doing is simply the command xdg-open followed by the path to the file, or the website address. Once the file starts opening, the Zenity dialog will close.

To keep it simple, the script above doesn't include any error messages. If you choose a file and nothing happens, check to make sure (a) that you have the correct file path or website address, or (b) that your file manager knows what application it should use to open a file of that particular type. Check the code, too: the spaces after [ and before ] are important!

The script depends on Zenity and the xdg-utils package. Last time I checked, both were included in all the major Linux distros.

Category: 
License: 

Comments

Anthony Mouser's picture

Problem: If you have a level of technical ability to configure this, you don't need the 'simplicity' or 'convenience' it provides.

IMO, a file-system if used as intended with directory structure is perfectly capable of storing information in a meaningful manner. The issue isn't cross-platform. The issue is showing the larger community how to store and archive files such that they can be easily retrieved sans search features.

The more we make the means for people to interact with a file-system the more we rely on dumbed down interfaces within which to access them.

Note, I'm not staunchly promoting that we all use the terminal to access files and applications, merely that each sensible environment provides a file manager, through which we can access files easily providing some form of meaningful system of cataloging has been made, vs dumping important files with junk in the desktop, or the other extreme allowing an OS to decide where the files should go - as in the arbitrary way some make media folders for music, that don't work like traditional folders (try moving files around manually, repeatedly inside of Windows 7's Music "Library", windows will decide that you don't need directories -- sometimes.

Thus the creation and failure of relational file systems, they act as arbitrary things in the middle between a users files and the user and are also subject to radical change on an ongoing basis. in stark contrast, once we learn how to store files in a directory structure such that an entire organization, or family can access files quickly - with a little prior education, that methodology will be relevant for many generations of OS past present and future.

Feel free to challenge my bigoted belief: what's the use in further simplifying and obscuring a user's data when operating systems at their core provide all that we need?

Bob Mesibov's picture

Interesting point of view. I once had an 'Active' folder in which I kept the files I now list in the launcher described above. It had the advantage that my daily backups were only of that 'Active' folder, since usually nothing else had changed on my hard drive.

I no longer have that folder. Instead, my frequently accessed files (12-15 of them, not the 4 shown in the illustration above) are back in a logically organised folder structure. I now do daily backups with rsync, so it doesn't matter what's changed and what hasn't: rsync will figure that out.

The big advantages for me of the favourites launcher over the 'Active' folder idea are first, that I can order the links in the launcher the way I want. If the frequency of access for a file changes, I can bump it up or down in the list easily.

The second advantage is that I find the 'unstable' part of the list easier to deal with than in a file manager. For a few days at a time I might need fast access to some files that normally sit dormant on the hard drive. Putting links to those files in the launcher, then deleting them, is easier for me than creating links to those files in my file manager, or shifting the files to a special folder.

I'd say it's a matter of personal choice!

Author information

Bob Mesibov's picture

Biography

I'm retired and live in Penguin, Tasmania, Australia. I love tinkering and prefer working with a keyboard, not a mouse.