Shell Programming and Scripting

I like the shell; don't get me wrong. But just to keep it interesting...

uname is shell, chomp is perl:

Code:

my $uname = `uname -n`; 
chomp $uname;

The below is not shell. It's a Symantec product about backing up servers.

Code:

`$nbadmin/bpgetconfig -i...`

I wonder how well that would interface with the shell?

...and then there is the arrays and string juggling, which is where perl shines.

a bash programming guru will disagree vehemently with this premise.

there's been very few, if any, situations i've been in that i wasn't able to use bash or awk. perl is a language i will caution people to be very careful with given the simple fact that in most cases, it requires the compilation, download/configuration of modules...which can be detrimental to existing applications on a system.

if perl is your favorite language, fine. stick to it but make sure you know it well enough that you dont have to rely or force your users to have to get modules in order for it to work.

matter of fact, just do a search in this forum alone and you will see very few people care to use perl. its usually awk/bash over perl.

I've turned this thread into a perl vs bash bash haven't I?
Didn't mean to.

Keeping the original poster in mind, whom we haven't heard from since; If someone wants to drop a bash script in his lap, go for it. It isn't going to improve on what he already has IMHO. Rather than leave us arguing about 'what's wrong with perl?', he should be telling us what is wrong with this particular script.

On my own behalf, I have apparently given the impression that I don't like bash. Quite the contrary, bash is what I know best and I use it for everything I do these days. The last time I used perl was to put together a gui app. Looking back I think Python would have been a better choice.

uname is not shell! Perl is using a shell here, but it doesn't need to. You should use fork() and exec() to run it more efficiently. But then you would need to set up pipes and such to connect it and worry about closing them after -- all the things BASH does without you even thinking about it. Perl has none of this. It shoves it all into BASH and forgets.

Or you could throw out the perl and not worry about any of it. If you're controlling external processes, you should be using shell, because perl is really bad at it.

( chomp() is not really needed here either. The shell makes do fine without it, but Perl takes things a little too literally. )

Perl is terrific at string juggling, but modern shells have arrays. Even better, they have and have always had lists...

It is already mostly "bash" code, in a membrane-thin wrapping of perl.

I don't think he's coming back at this point, we wanted him to do too much work.

Hi ongoto...
Let me know when PERL, Python or nearly any other language for that matter, can do this:-

Is there anything the shell can't do?

I have made the *NIX shell my language of choice now and all but abandoned Python, I have little experience of PERL however.

EDIT:
BTW, I am looking into FFT stuff for another possible project using the shell...

Good. We all agree.

The shell is the coders swiss army knife. But to use it exclusively out of prejudice is cheating yourself. OO languages do have a lot to offer if you need to pass around groups of data all in one go and that sort of thing. The shell now has associative arrays, but they don't stay ordered. Try looping through them. Try passing an array to a function. There goes your indexes. But that doesn't make the shell bad. You're gonna hit a wall in the others too.

In Perl you always end up making calls to the shell because it saves work. Why write a block of Perl code to do 'uname -r'? On the other hand, Perl lets you do things like "do something unless condition", or "if condition, etc" all in one statement. If Perl can save you some work, then why not use it.? Same with Python and the others mentioned. What would we shell coders do without Awk and Sed and Grep?

Ya got tools that are metric, some are std SAE, and then there are the 'star' bits and the universal sockets. But you can't cut down a tree with a phillips!

Cheers mates

Awesome.
AE6UB said that.