Opinion on best practice...

Grant Edwards invalid at invalid.invalid
Wed Feb 6 16:18:09 CET 2013


On 2013-02-06, Steven D'Aprano <steve+comp.lang.python at pearwood.info> wrote:
> Chris Angelico wrote:
>
>> Python is not an "excellent option". It's a bad fit for shell
>> scripting, it just happens to be way better than a weak shell. Having
>> grown up on command.com, I found OS/2's cmd.exe to be a massive
>> improvement, and Windows's cmd.exe to be rather less impressive... but
>> both of them pale into insignificance compared to bash.
>
> I have to disagree with much of this. bash is a poorly designed
> language which, in my opinion, is only good enough for short (under
> 20 lines) throw-away scripts.

And the OP wanted to write someting that was what, about 3 lines?

> This is how you test whether something is not the name of a directory:
>
> [[ -d $dir ]] || {
>   echo "$FUNCNAME: $dir is not a directory" >&2
>   return 2
> }

It can be written more clearly.

> http://www.bashcookbook.com/bashinfo/source/bash-4.2/examples/functions/emptydir
>
> Arithmetic requires either calling an external program, or special magic
> syntax:
>
> z=`expr $z + 3`
> i=$(( i + 1 ))

Agreed: Bash is not good at math.  It should not be used for numerical
analysis.

> Spaces are magic -- these two lines do radically different things:

So?  Leading spaces are magic in Python.

> bash is even more weakly typed than Perl. As far as I can tell, bash
> is completely untyped -- everything is text, all the time, even
> arrays.

Correct.  In bash, everything is a string.

If you're doing something other than manipulating files (and therefore
filenames and paths), then bash is probably the wrong language to use.

-- 
Grant Edwards               grant.b.edwards        Yow! Are we wet yet?
                                  at               
                              gmail.com            



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