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Moreshell tricks: first class lists, jq, and the es shell

alurm.github.io

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Re: Moreshell tricks: first class lists, jq, and the es shell

#11

Post by packetlost »

delta_p_delta_x wrote: post #4

I was about to comment with my usual 'why not PowerShell', but it seems the author acknowledges this anyway at the end: > I’ll quote Rich’s sh (POSIX shell) tricks to end this: > I am a strong believer that Bourne-derived languages are extremely bad, on the same order of badness as Perl, for programming, and consider programming sh for any purpose other than as a super-portable, lowest-common-denominator platform for…

This is why I use Plan9's rc shell for a lot of my scripting needs. It's dramatically nicer to write but even more nice to read.

Re: Moreshell tricks: first class lists, jq, and the es shell

#12

Post by calmbonsai »

jeffrallen wrote: post #2

I review shell scripts from beginner ops people. I would not approve any of this stuff. Once you need this complexity in shell, you need other things you should be getting from the language's stdlib. So I'd ask them to switch to Python or Go. Do not fall into the trap of big complex shell scripts.

I'll go further.

Shell is great for personal or local-group/team automation, but outside of a bootstrap, it should _never_ be used for anything in deployed production.

The 3 main issues are hidden deps, error handling, and performance.

Re: Moreshell tricks: first class lists, jq, and the es shell

#13

Post by kjellsbells »

I know Perl gets no love here, and for good reason sometimes, but I have a hard time believing that code full of syntactical characters like

  if .["found"] then
    . | .after += [$arg]
  elif $arg == "--" then
    . | .found = true
  else
    . | .before += [$arg]
  end
or

  for (i = $indicies) if { ~ $*($i) -- } {
      before =
...is more readable and maintainable than:

  my ($before, $after) = split /\s*--\s*/, $input;
  my @list1 = split ' ', $before;
  ...

Re: Moreshell tricks: first class lists, jq, and the es shell

#14

Post by alurm »

chubot wrote: post #9

let’s implement split-by-double-dash, a function (or a program) that would return two lists: args that come before -- and ones that come after. split-by-double-dash a b c -- d e f should return the lists [a, b, c] and [d, e, f] FWIW in YSH ( https://oils.pub/ysh.html ), you can do this in a style that's like Python and JavaScript, but you can also combine it with shell idioms. First create it and pretty print it: ysh…

YSH looks very nice here, thanks. I thought to mention YSH, but have no experience with it, so I hoped you would comment.

(I guess we're duplicating threads at this point :D)

Re: Moreshell tricks: first class lists, jq, and the es shell

#15

Post by floydnoel »

jeffrallen wrote: post #2

I review shell scripts from beginner ops people. I would not approve any of this stuff. Once you need this complexity in shell, you need other things you should be getting from the language's stdlib. So I'd ask them to switch to Python or Go. Do not fall into the trap of big complex shell scripts.

Overall I agree, but I think developers usually err the other way, where they are afraid of running any shell commands outside of invoking their developer tools.

I really enjoyed this article because I found it refreshing- it felt like it was intended for hackers. I love to learn more about different shells and functionality vs yet another unicorn's latest product announcement.

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