David Brodbeck wrote:
> In particular, Bash's "test" (aka "[")
operator has pitfalls. Testing for an empty variable, for example, is
awkward. If you do:
if [ $foo == "" ]
Yeah, prefer:
if not foo:
do something
-- there are few languages where it's quite so easy to test conditions
like, 'is this a directory?'.
Bash undoubtedly is more concise than this but I'd contend it is no easier.
import os
if os.path.isdir(somedir):
print "It's a dir, Jim!"
Bash is great if you need to glue together a bunch of existing utilities
to do something. You can pipe output directly from one utility to
another with an ease that doesn't exist in most other languages, which
tend to make it complicated to launch other processes. Doing complex
tasks with a series of simple utilities is sort of what Unix is all about.
I contend that is more a was than an is. Shell filled a niche years ago
that now has largely shrunk to special cases. So far in this thread there
have been two example total of where a shell script might be better for more
than 2 minutes over a proper scripting language. Generally by the time any
shell script starts piping 2-3 things I just convert it to Python and get it
done far easier and far faster. Mainly because I don't have to jump through
the hoops the warts above present.
Besides, until operating systems start having init scripts written in
Perl or Python, being able to write shell scripts is going to be an
essential system administration skill. ;)
Quite frankly they should now. Any time I've had to throw something into
init scripts I've done it in Python. The last example was a script to
determine whether my laptop was running Debian under VMWare or natively and if
natively which dock it was plugged into. That was 7 years ago. :)
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