Re: for loop with parameter expansion in zsh vs. bash

[lilydjwg <lilydjwg@gmail.com>]

On Tue, Nov 03, 2015 at 07:52:51AM +0100, Alexander Skwar wrote:
> Hello
> 
> I've got a variable, where seperate values are limited with a delimiter.
> Let's say PATH with : (but the question is general).
> 
> With bash, I can easily create a for loop which loops over all the
> elements, when I have bash replace the ":" with a " ", like so: ${PATH//:/
> }.
> 
> a@ubuntu-notebook:~$ echo $PATH
> /home/a/Applications/go/bin:/home/a/bin:/opt/bin:/opt/sbin:/usr/local/sbin:/usr/local/bin:/home/a/Applications/copy/x86_64:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/home/a/Applications/adt-bundle-linux-x86_64/sdk/platform-tools:/home/a/Applications/btsync:/home/a/.rvm/bin
> 
> a@ubuntu-notebook:~$ for e in ${PATH//:/ }; do echo e: $e; done
> e: /home/a/Applications/go/bin
> e: /home/a/bin
> e: /opt/bin
> e: /opt/sbin
> e: /usr/local/sbin
> e: /usr/local/bin
> e: /home/a/Applications/copy/x86_64
> e: /usr/sbin
> e: /usr/bin
> e: /sbin
> e: /bin
> e: /usr/games
> e: /usr/local/games
> e: /home/a/Applications/adt-bundle-linux-x86_64/sdk/platform-tools
> e: /home/a/Applications/btsync
> e: /home/a/.rvm/bin
> 
> 
> In zsh, the same for loop does not work (like it does in bash):
> 
> 7:51% for e in ${PATH//:/ }; do echo e: $e; done
> e: /home/a/Applications/go/bin /home/a/bin /opt/bin /opt/sbin
> /usr/local/sbin /usr/local/bin /home/a/Applications/copy/x86_64 /usr/sbin
> /usr/bin /sbin /bin /usr/games /usr/local/games
> /home/a/Applications/adt-bundle-linux-x86_64/sdk/platform-tools
> /home/a/Applications/btsync
> 
> 
> As you can see there, zsh had only 1 iteration of the for loop.
> 
> What would be the zsh way to loop over elements, which are delimited by a
> ":" (or "," or ";" or whatever)?
> 
> Thanks a lot,

% for e in ${=PATH//:/ }; do echo e: $e; done

zsh has sh_word_split option unset by default, so use ${=var} to request
word splitting explicitely.

I like this behaviour very much, because I don't need to quote nearly
every variable :-)

PS: there is a coresponding $path array, and you can tie your own variables like this:

export -TU PYTHONPATH pythonpath 2>/dev/null

Re-tying a variable fails for zsh 4.x so I have to redirect the error
message to the black hole. And '-U' is for uniq to remove duplicates.

-- 
Best regards,
lilydjwg