Extras: Add manual link for advanced bash scripting guide

[JimCircadian]

Hello

I suggest under the "Manuals" section of Extras to add a link to the "Advanced Bash Scripting Guide" from The Linux Documentation Project, which I have suggested to people for many years and is always well received as a reference. I think it's probably the most comprehensive guide for aspiring shell programmers and, by linking to the project site in general, it'll open doors for exploration of further materials.

Of course, absolutely happy to raise the PR should people be in agreement 😄

Thanks!

[bkmgit]

Thanks for the suggestion. This resource is very helpful, but may be too involved for some attendees. Perhaps the
BASH Programming - Introduction HOW-TO is more suitable?

[JimCircadian]

That's a good shout @bkmgit, certainly don't want people being put off!!! I'll raise it via my fork, thanks for getting back to me!