Bash is a great argument for the fact that it is not so much the features of the language that matter, but what ecosystem it is a part of. Bash is popular because it is the default scripting language of the shell in Unix. Javascript is popular because it is in all the browsers. C is popular because it is the default compiled language of Unix. Objective-C became popular because it was the default programming language of the iPhone.
Yeah this explains why and predicts that Kotlin and Swift are popular, because Android and iOS now use them.
It also explains PHP, because PHP was tightly integrated with Apache via shared library, and in the 90's, lots of hosting providers were spinning up LAMP.
So basically if you wanted to buy hosting in the 90's, you could pay $20/month for shared PHP, or $200/month for a dedicated box running Perl.
PHP creator Rasmus had a good talk about that recently. So shared hosting was essentially "remote OS" that was cheap.
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Exceptions to the rule: Python and Ruby. People installed them because they were nicer languages, and mainly used them on the server side. But Python even made it to the client side in many instances because people like the language! (Dropbox, IPython/Jupyter, etc.)
bash was the default on Linux, which was huge. Other Unixes like Solaris and BSDs used other shells, but yeah it does seem true that bash was helped along by Linux.
I think Linus said that bash was literally the first program that ever ran on Linux, which made sense. Before that I guess bash was run on Solaris and commercial Unixes, and wasn't that popular.