Zsh-autoquoter makes shell quoting slightly less annoying • Hacker News Board

Re: Zsh-autoquoter makes shell quoting slightly less annoying

#11

Post by weinzierl » Tue, May 10, 2022, 3:57 PM UTC

mmastrac wrote: post #3

The shell quoting rabbithole goes pretty deep, especially when you want to preserve the whitespace within arguments. Has this been solved generally yet? I suspect it requires full knowledge of whatever shell is running on the other side of SSH.

An autoquoter is a bit too much magic for me, but I wish there was a quote explainer. Much like 'cdecl' for C declarations, a program that explains expressions with quotes in plain English. Problem, I guess, is that shell quoting depends on the context where it is used.

Re: Zsh-autoquoter makes shell quoting slightly less annoying

#12

Post by chasil » Tue, May 10, 2022, 4:02 PM UTC

orsenthil wrote: post #4

I am still afraid to switch from Bash to Zsh, because these are things I don't fully understand and will find it hard to debug if _something_ breaks. Is something like this available for bash?

It is useful to try your scripts in a POSIX shell that avoids non-standard extensions. The best known is the Debian dash reroll of the Almquist shell, but there are other implementations (I've heard of mrsh and gsh, and the one in OCaml).

POSIX shells do not support arrays, and many other common bash extensions. However, dash is very small, and very fast (4x faster than bash according to some sources).

Scripts written for the POSIX shell are maximally-portable.

Re: Zsh-autoquoter makes shell quoting slightly less annoying

#13

Post by jchw » Tue, May 10, 2022, 4:17 PM UTC

NegativeLatency wrote: post #10

One of the nice things about fish is that it does this when pasting: https://github.com/fish-shell/fish-shell/issues/967

PowerShell does this too, at least for URLs. That said, it’s a true pain in the ass when it kicks in incorrectly, which unfortunately does happen.

Re: Zsh-autoquoter makes shell quoting slightly less annoying

#14

Post by ianthehenry » Tue, May 10, 2022, 4:25 PM UTC

haroldp wrote: post #8

mmastrac wrote: post #3

The shell quoting rabbithole goes pretty deep, especially when you want to preserve the whitespace within arguments. Has this been solved generally yet? I suspect it requires full knowledge of whatever shell is running on the other side of SSH.

Just thinking of one of OP's examples, his (very cool) autoquoter allows him to type: > ssh user@host awk '{print $1}' file.txt And have the "$1" quoted or escaped so that it's interpreted as an awk keyword on the remote system. But what if I actually want it interpreted as a shell variable that should be expanded on the local or remote system? How does it know? Why is shell quoting still so hard?

This is a good question without a good answer. zsh-autoquoter doesn't know -- it doesn't know anything, really. The only thing it does is pass the literal string you type as an argument to the command you run (in this case, ssh).

So you could get the "treat it as a shell variable on the remote server" behavior by writing this instead:

    ssh user@host awk "{print $1}" file.txt

But there's no way, using zsh-autoquoter, to say "yeah but this particular part of the string should not be escaped; let my local shell handle it."

Re: Zsh-autoquoter makes shell quoting slightly less annoying

#15

Post by Bayart » Tue, May 10, 2022, 6:37 PM UTC

orsenthil wrote: post #4

I am still afraid to switch from Bash to Zsh, because these are things I don't fully understand and will find it hard to debug if _something_ breaks. Is something like this available for bash?

I use Zsh for CLI and Bash for scripting. Never ran into any problem, production-wise.

Re: Zsh-autoquoter makes shell quoting slightly less annoying

#16

Post by re » Tue, May 10, 2022, 6:41 PM UTC

NegativeLatency wrote: post #10

One of the nice things about fish is that it does this when pasting: https://github.com/fish-shell/fish-shell/issues/967

So can Zsh -- this functionality has shipped with Zsh since for several years, though not enabled by default.

See https://github.com/zsh-users/zsh/blob/master/Functions/Zle/b... or https://github.com/zsh-users/zsh/blob/master/Functions/Zle/b...

Re: Zsh-autoquoter makes shell quoting slightly less annoying

#17

Post by drw » Tue, May 10, 2022, 7:59 PM UTC

More flexible would be a double-quote-region widget which can be applied arbitrarily to any region of a command line:

    emulate -L zsh

    if [[ "$REGION_ACTIVE" -eq 0 ]]; then
        return
    fi

    if [[ "$MARK" -le "$CURSOR" ]]; then
        left_region_bound="$MARK"
        right_region_bound="$CURSOR"
    else
        left_region_bound="$CURSOR"
        right_region_bound="$MARK"
    fi
    length_region="$((right_region_bound - left_region_bound))"

    before_region="${BUFFER:0:$left_region_bound}"
    region="${BUFFER:$left_region_bound:$length_region}"
    after_region="${BUFFER:$right_region_bound}"

    quoted_region="${(qqq)region}"
    cursor_offset="$(($#quoted_region - $#region))"

    BUFFER="$before_region$quoted_region$after_region"
    CURSOR="$((CURSOR + cursor_offset))"
    REGION_ACTIVE=0

bind with eg

    zle -N double-quote-region
    bindkey '\e"'  double-quote-region

Re: Zsh-autoquoter makes shell quoting slightly less annoying

#18

Post by Beltalowda » Tue, May 10, 2022, 8:03 PM UTC

haroldp wrote: post #8

mmastrac wrote: post #3

The shell quoting rabbithole goes pretty deep, especially when you want to preserve the whitespace within arguments. Has this been solved generally yet? I suspect it requires full knowledge of whatever shell is running on the other side of SSH.

Just thinking of one of OP's examples, his (very cool) autoquoter allows him to type: > ssh user@host awk '{print $1}' file.txt And have the "$1" quoted or escaped so that it's interpreted as an awk keyword on the remote system. But what if I actually want it interpreted as a shell variable that should be expanded on the local or remote system? How does it know? Why is shell quoting still so hard?

> Why is shell quoting still so hard?

The problem with the awk example here specifically is that you're mixing two different languages (shell and awk), and that's always going to be painful to a degree. Doing something like running Python code directly from a Ruby script also isn't fun, especially not if you want Python variables in that Ruby script.

And to make it extra fun in the ssh you're also adding a second shell (on the system you're sshing to), so you have to think about 1) your machine's shell, 2) the host's shell, and 3) awk.

So yeah ... that's going to be tricky, but in this case it's not really a shell problem as such.

Re: Zsh-autoquoter makes shell quoting slightly less annoying

#19

Post by Beltalowda » Tue, May 10, 2022, 8:09 PM UTC

__del__ wrote: post #6

dmd wrote: post #5

Earlier quoted context omitted.

It's puzzling to me that people still think of zsh as "that newfangled shell I'm not sure about yet". Bash came out in 1989. Zsh came out in 1990.

i use zsh, but i often invoke bash just to make sure some behavior is "normal" rather than zsh-specific, or specific to how i wrote my .zshrc last decade [and haven't changed]. i don't think it's about the newfangledness; i think it's about the potential for subtle differences in syntax which scare people away from zsh.

I think the initial setup can be quite daunting; unlike bash, which never seemed to have moved beyond 1990, zsh added a lot of features, many of which are very useful (some of which less so, like csh-compatibility things) but there's a lot of it, and the defaults are somewhat bare-bones. Hence things like oh-my-zsh, which is quite intimidating in its own way.

The fish shell "fixed" a lot of that by adding more or less the same feature-set as zsh but without the extensive configurability, which is a really great trade-off if the fish defaults work well for you (they don't for me personally though).

Re: Zsh-autoquoter makes shell quoting slightly less annoying

#20

Post by a1369209993 » Tue, May 10, 2022, 10:00 PM UTC

NegativeLatency wrote: post #10

One of the nice things about fish is that it does this when pasting: https://github.com/fish-shell/fish-shell/issues/967

Honestly, the "when pasting" part seems very much a case of solving the wrong problem there. For my shell, I just had any unquoted ':/' or ':?' mark the word as a url, causing glob characters (and some others like '&', for obvious[0] reasons) to be implicitly quoted until the end of the word.

0: assuming you've seen a url like http://example.com/foo?bar=1&baz=2 before