shell-quote-argument escapes '='

shell-quote-argument escapes '='

[R. Diez]

Hallo all:

I am running a self-compiled Emacs version 26.2 on Ubuntu 18.04.4 LTS. I normally use Bash as a shell.

When I evaluate the following in Emacs:

  (shell-quote-argument "a=b")

I get:

  "a\\=b"

That's wrong, because it does not work in Bash:

  $ echo "a\\=b"
  a\=b

But even if I am getting confused with Emacs' string escaping, echo "a\=b" does not work either.

I am looking for the equivalent in Emacs for Bash' printf "%q" escaping/quoting:

  $ printf "%q" "a=b"
  a=b

I though I might just copy and modify shell-quote-argument, but it is too complicated for my limited Lisp skills.

I do not need any flexibility or configuration, I just need to emulate the behaviour of Bash' printf "%q".

Thanks in advance for any help,
  rdiez

Re: shell-quote-argument escapes '='

[Stefan Monnier]

>   (shell-quote-argument "a=b")
>
> I get:
>
>   "a\\=b"

Which is the printed representation of the string that contains
4 characters:

    a\=b

> That's wrong, because it does not work in Bash:
>
>   $ echo "a\\=b"
>   a\=b

You're not supposed to put quotes around nor to double the backslash:

    $ echo a\=b
    a=b
    $


-- Stefan

Re: shell-quote-argument escapes '='

[Philipp Stephani]

Am Fr., 24. Apr. 2020 um 15:29 Uhr schrieb Stefan Monnier
<monnier@iro.umontreal.ca>:
>
> >   (shell-quote-argument "a=b")
> >
> > I get:
> >
> >   "a\\=b"
>
> Which is the printed representation of the string that contains
> 4 characters:
>
>     a\=b
>
> > That's wrong, because it does not work in Bash:
> >
> >   $ echo "a\\=b"
> >   a\=b
>
> You're not supposed to put quotes around nor to double the backslash:
>
>     $ echo a\=b
>     a=b
>     $
>


Note that those two aren't the same. The command

a=b

sets the variable 'a' to the string 'b'. The command

a\=b

runs a function/command/binary called 'a=b'. So not quoting = (i.e.
replicating the printf %q behavior) would be a breaking change.