Running a .sh to execute multiple commands

Question

I was curious how I would go about running multiple commands via shell script.

For example, just to try it out, I'd like to be able to connect a .desktop to a .sh that will run all the update codes so I don't have to type it out. I know how to execute a single command via a .sh, not multiple.

Any way?

Answer 1

Simple really - you need to separate the commands. For instance this:

#!/bin/bash
sudo apt-get update
sudo apt-get upgrade

will update the package lists, and then the packages. Another possibility is this (probably better, as the && will only allow the upgrade command to run if the update exits successfully):

#!/bin/bash
sudo apt-get update && sudo apt-get upgrade

This should run the commands for updating the list of packages and then the package themselves. This would need to be saved into a text file (e.g. updatescript in the home directory). You can then make it executable by running:

 chmod +x ./updatescript

or by right clicking on the file and making it executable in its properties:

and run it with this in terminal:

 ./updatescript

Note(s):

There is an option (-y) available that can be used with the upgrade command so it does not prompt before upgrading the packages. It is a good idea to check what apt-get is doing before it upgrades the packages, as it may/will do something stupid or something you don't want it do. More info on options like this can be found by running man apt-get.

This also means it is more ideal to use the terminal to run the script, as you can check what it is updating, and then run it. If you want a GUI way to run the updates, use the software-center as that it is what it is for.

Answer 2

Just to add a few points to the excellent answer by @Wilf,

you can run commands in paralell if you want for any reason, for example, an autostart script for OpenBox might look like this:

#!/bin/bash

nitrogen --restore &
tint2 &
tilda

This will set a background image using nitrogen, start the panel tint2 and start the Quake3-style dropdown console tilda, all at the same time. This is useful if you don't need a program to finish before you launch the next one. Not the case for apt-get update and apt-get upgrade though!

Notice the & sign at the end of each line. This will cause the shell to fork that process into the background and continue execution. Note how it's different from &&, which is basically an and sign, command_1 && command_2 will executecommand_1 and if it exits with success, only then run command_2, while command_1 & command_2 will start the second right after the first.

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Also, you could just stack commands to have them executed serially, like so:

#!/bin/bash

apt-get update
apt-get upgrade

This will run apt-get upgrade after apt-get update is finished, but regardless of the result. So even if, for example, the update quits with a network error, the upgrade will still be run.

You can also do this in one line, using the ; sign: apt-get update ; apt-get upgrade. Again, this solution is not optimal for these particular commands, but it might come in handy in other situations.

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One quick final point, you can also break lines containing && as such:

command_1 &&
command_2

This will be the same as command_1 && command_2.