Bash: unexpected behavior using a variable containing directory with escaped spaces

Question

This is a follow up to https://apple.stackexchange.com/questions/52459/ and is about an unexpected behavior in bash. To summarize what's in that link, the problem is to copy the current directory in Terminal to a temporary variable, say the pasteboard, and use that to switch directory in a different Terminal window. The solution provided there pretty much nails it in the most efficient way! However, when I actually try changing directories using this temporary variable with the correctly escaped directory name, it seems to not work right in bash.

My minimum working example is as follows:

alias cwd='printf "%q/\n" "$(pwd)"'

Now in a terminal:

>$ mkdir tmp
>$ cd tmp
>$ mkdir test\ dir
>$ cd test\ dir
>$ cwd | pbcopy

In a new terminal:

>$ echo "$(pbpaste)"
/Users/foo/tmp/test\ dir/
>$ cd $(pbpaste)
-bash: cd: /Users/kaushik/tmp/test\: No such file or directory
>$ cd "$(pbpaste)"
-bash: cd: /Users/kaushik/tmp/test\ dir/: No such file or directory

I'm quite at loss in trying to figure out what I'm doing wrong. The only thing I'm certain of is that this is a bash problem and not something that's cropping up on OS X.

Thanks for your help on this and, by the way, it turns out that I had to finally, after all these many years, end up writing my first stack overflow post!

Why are you escaping? Use `%s` instead of `%q`, and `"$(pbpaste)"`, and you should be okay. The problem is that you have a string which has a literal backslash in it, and that is obviously not the directory's name. — Amadan, Apr 09 '15 at 05:18
Reading your link, the question is specifically how to get the PWD into the clipboard *escaped*. You need it escaped if you will paste it in command line as an argument, not if bash is getting it as programmatic input as in your case. — Amadan, Apr 09 '15 at 05:24
Hey @Amadan: Thanks; that was really quick and that solved it! Such a stupid oversight on my part; I blindly went with the solution provided to the other question without figuring out what %q stood for. (To be honest, I presumed you would need to escape it explicitly since that's how I create a directory with spaces using pwd.) — Kaushik Kalyanaraman, Apr 09 '15 at 05:28
:) Actually, seeing how you're just doing a `cd`, you don't even need `printf` at all, just `pwd | pbcopy`. — Amadan, Apr 09 '15 at 05:30
@Amadan: Yeah, that's what I always use. However, all these years, I never had directories with spaces and I have been using command substitution without quotes. Of course, that fails with directories with spaces (something I've warmed up to only recently); hence I went looking for solutions! But, simply using pwd | pbcopy works! Thanks again! — Kaushik Kalyanaraman, Apr 09 '15 at 05:34

Amadan · Accepted Answer · 2015-04-09T05:50:20.743

Copied from comments: The linked answer specifically asks for the escaped PWD suitable for pasting, but you want a programmatic input where escaping is counter-productive. Just do pwd | pbcopy and cd "$(pbpaste)".

EDIT:

(To be honest, I presumed you would need to escape it explicitly since that's how I create a directory with spaces using pwd.)

The issue is that command-line parser only does one pass of unescaping. In case of cd foo\ bar, the space is unescaped. In case of cd $(pbpaste), there is nothing to unescape; then pbpaste's literal output is put into the argument list.

Bash: unexpected behavior using a variable containing directory with escaped spaces

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