Things I Wish I'd Known About Bash • Hacker News Board

Re: Things I Wish I'd Known About Bash

#11

Post by skj » Sat, Jan 06, 2018, 2:50 PM UTC

francis-io wrote: post #9

Sir_Cmpwn wrote: post #4

#0: If you're writing scripts that are destined for other users, use POSIX sh instead.

Can you explain why?

Not all systems have bash.

Re: Things I Wish I'd Known About Bash

#12

Post by wirrbel » Sat, Jan 06, 2018, 2:56 PM UTC

francis-io wrote: post #9

Sir_Cmpwn wrote: post #4

#0: If you're writing scripts that are destined for other users, use POSIX sh instead.

Can you explain why?

less magic (which you start to care for if you have to use other people's magic), easier to port stuff to zsh, etc.

Re: Things I Wish I'd Known About Bash

#13

Post by 0942v8653 » Sat, Jan 06, 2018, 3:00 PM UTC

thibran wrote: post #5

Does fish-shell have an equivalent for '<()'?

https://fishshell.com/docs/current/commands.html#psub

Re: Things I Wish I'd Known About Bash

#14

Post by indigodaddy » Sat, Jan 06, 2018, 3:06 PM UTC

Can someone explain :h as the article's description was not clear at all to me what was going on there.

Re: Things I Wish I'd Known About Bash

#15

Post by mmjaa » Sat, Jan 06, 2018, 3:11 PM UTC

indigodaddy wrote: post #14

Can someone explain :h as the article's description was not clear at all to me what was going on there.

Yeah, I couldn't make that work for me (on Linux or MacOS) .. although I'd love it if there were a way to quickly get 'just the directory' or 'just the filename' in bash with a shortcut, instead of having to resort to $(dirname blah) and so on .. I'm sure there is some way but :h doesn't look to be the shortcut as expected.

Re: Things I Wish I'd Known About Bash

#16

Post by yjftsjthsd-h » Sat, Jan 06, 2018, 3:12 PM UTC

Sir_Cmpwn wrote: post #10

francis-io wrote: post #9

Earlier quoted context omitted.

Can you explain why?

For portability. bash is not available everywhere, but POSIX sh is a requirement of POSIX so you can expect it to be there.

Exactly: GNU bash is on most GNU/Linux systems, but:

* mac OS uses an ancient version of bash

* Embedded systems use busybox sh

* Android uses its own version of sh

* None of the BSDs come with bash, since, y'know GNU licensing

EDIT: Formatting

Re: Things I Wish I'd Known About Bash

#17

Post by joshbaptiste » Sat, Jan 06, 2018, 3:13 PM UTC

Hang out in #bash on IRC Freenode and you will be a Bash jedi http://mywiki.wooledge.org/BashFAQ best resource IMO for quick Bash syntax lookups as I always need to refer to the BashFaq to remember parameter expansion sub-string retrieval.

  parameter     result
  -----------   ------------------------------
  $name         polish.ostrich.racing.champion
  ${name#*.}           ostrich.racing.champion
  ${name##*.}                         champion
  ${name%%.*}   polish
  ${name%.*}    polish.ostrich.racing

Re: Things I Wish I'd Known About Bash

#18

Post by thibran » Sat, Jan 06, 2018, 3:19 PM UTC

0942v8653 wrote: post #13

thibran wrote: post #5

Does fish-shell have an equivalent for '<()'?

https://fishshell.com/docs/current/commands.html#psub

Thanks a lot. Shells have so many features it's easy to miss one.

Re: Things I Wish I'd Known About Bash

#19

Post by wand3r » Sat, Jan 06, 2018, 3:21 PM UTC

I understand "the hard way" is a commonly used phrase but it does seem a bit infringing on Zed Shaw's entire series Learn Code the Hard Way. Easily confusing. Other than that, good work

Re: Things I Wish I'd Known About Bash

#20

Post by amelius » Sat, Jan 06, 2018, 3:21 PM UTC

Bash has a huge number of little shortcuts that are difficult to learn. When one encounters a sequence of symbols like $(...), it is difficult to Google for its meaning. The reason shells nevertheless have these shortcuts is of course because they are shells: from the commandline it can be very convenient to use shortcuts.

But, in my opinion, that's where it should stop: one shouldn't use a shell language for scripting. In scripts, it is simpler to use more verbose and clear constructs, because most editors are very powerful and provide shortcuts themselves.