sys utilities written in Perl versus shell scripts, which is better?

If you are thinking about writing scripts for a business then you should think about people that will come after you to support the systems. These people will almost certainly know shell commands but may not know Perl. So Perl is not so universal as you might think. It may be available on many systems but that doesn't mean that everyone knows how to program in it.

With perl, it isn't as errrrr. Hard to understand I guese, like it would be in perl. sh script: ps -x | grep processname | awk

But, your right. Most people will reconize more commands that are being done with shell scripts. They might have some issues with the variables and such, but I guese they could figure them out.

perl just lends itself so often to system applications though, even if they could be done in shell scripts.

eh, I think Ill just look at the complexity and decide from there.

Thanks for the comments, much appriceated.

Dan

Really, you should just use whichever one suits the task at hand and your own preferences at any given moment, unless you're in a work environment that specifically favors one over the other for some reason.

In the general sense, shell scripts are pretty universal: every 'nix system can run a shell script. On the other hand, different systems default to a different shell (for instance, almost every Linux system in the world defaults to bash, while almost every *BSD in the world defaults to csh or tcsh. Each proprietary UNIX vendor chooses its favorite shell as well. As your shell scripts start involving stuff other than simply saving calls to external utilities in a text file, they become less and less universal -- besides which, the shebang line specifies the shell you're using.

Perl, meanwhile, is basically the same on every system where Perl is installed, unless someone hasn't updated his Perl version since 1995 or something like that.

Some tasks are already accomplished easily through the use of a short pipeline containing a couple of system utilities, while others need to be constructed almost from scratch -- in the former case, a shell script is usually more appropriate, and in the latter, a Perl script is generally better.

I use both. It would probably behoove you to do much the same, really. Pick a language -- shell or Perl -- based on the task at hand, and make your job as easy as possible. Of course, Perl's more fun, so I tend to lean more toward using Perl when the options seem about equivalent otherwise.

I'm use to using it on BSD systems.
Actually apotheon, those were just bogus examples with regard to the ps -x | awk. I more often pipe grep's into awk to pull out specific columns, then perform mathematics. Also, awk gives you the ability to do simple array work if your splicing stuff out. Say you awk with an separator character of ~(config file field separator that I use a lot), then you want to split apart a value within that. Here is an actual value of me checking if a value was passed with a flag. Flag as passed, -b. But this flag can appear as -b or -b
[pre]#
# Check to see if a threshold value was passed with the switch.
#
TmpThreashold=`echo $Passed_values | awk \
' {if (length($1) > 2) {
Threashold=substr($1,3,length($1))
print Threashold
}
}'`[/pre]
That is from a firewall script that I did that parses through the auth.log. That is also a very good example of a script that I should have wrote in Perl using regular expressions.

That was my question, which is both more efficient and cleaner. shell scripts or Perl? I'm definitely leaning toward always using Perl anymore. Other then one liner shell scripts with piping, Perl just seems more versatile and cleaner.

Dan

The one that works in all situations is the best.

1) Mostly Unix systems use this. In Linux it would be ps x

2) I donno, just doing the same code in perl

As for the shebang, I have to say I should have run it first ;-)