This guide will introduce you to Bash multi-threaded coding basics.
What Ismulti-threaded programming?
As far as the user is concerned, a single thread was executing a single sleep of one second.
In the second line, we have two one-second sleep commands.
Normally, one would terminate a command by using a semicolon (;).
Doing so would execute the command and only then proceed to the next command listed behind the semicolon.
The||is the opposite of&&and will execute the second command only if the first command failed.
Additionally,Bash Process Termination Hacksmay be of interest.
As we can see ourdoneoutput shows in 1.005 seconds and thus the twosleep 1commands must have run simultaneously.
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In essence, one may think about multi-threaded coding in Bash as starting several background threads.
It was rather the (sub)shell which was started when./rest.shwas executed.
Let’s change our script by addingjobsinside the script.
We can also see their PID’s (Process Identifiers).
These PIDs are very important when it comes to handling and managing background processes.
After 10 seconds, our first thread exists, and we are notified of the same.
Wrapping up
In this article we explored Bash multi-threaded scripting basics.
We introduced the background process operator (&) using some easy-to-follow examples showing both single and multi-threadedsleepcommands.
We also explored thejobscommand to see running background threads/processes.
If you enjoyed reading this article, have a look at ourBash Process Termination Hacksarticle.
