topic Re: goto command in shell in Operating System - HP-UX

goto command in shell

andi_1 — Wed, 22 May 2002 13:34:16 GMT

Hi guys,

Is there a goto command in shell? And if there is one, does anyone know how to use it?

Thank you!

Re: goto command in shell

Justo Exposito — Wed, 22 May 2002 13:49:21 GMT

Hi Andi,

As I know there is not a goto command in shell, but if you think there is not necessary to do the things that you want to do.

If you want I can help you with your script.

Regards,

Justo.

Re: goto command in shell

James R. Ferguson — Wed, 22 May 2002 13:59:15 GMT

Hi:

Sorry, no. However, in Posix shell (or 'ksh') you have 'break' to exit from a 'for' 'select', 'until', or 'while' loop, and 'continue' to resume the next iteration of the same (for, select, until, while); and 'return' to immediately exit a function.

Regards!

...JRF...

Re: goto command in shell

A. Clay Stephenson — Wed, 22 May 2002 14:03:00 GMT

There is no goto in the Bourne, Korn, or POSIX shell but csh does have one. You should be able to circumvent the need for a goto with a 'break' to exit from the enclosing while, until, for, or select loop.

Re: goto command in shell

Bill Hassell — Wed, 22 May 2002 14:15:18 GMT

As Edsgar Dijkstra pointed out in the 60's, the goto is harmful, which is one of the reasons that higher level languages accomplish tasks in a top down manner. Looping is handled with for/while/until and bailing out due to errors or special exits is accomplished with functions, traps and break or continue.

Nothing messes up easily understood code better than a goto.

Re: goto command in shell

Paula J Frazer-Campbell — Wed, 22 May 2002 14:21:29 GMT

Hi

As all have said no goto but calling a script from a script can be made to behave like a goto.

Paula

Re: goto command in shell

James R. Ferguson — Wed, 22 May 2002 14:39:31 GMT

Hi (again):

Bill made me chuckle, having been around awhile... Be glad for 'break' and 'continue' at least. I once developed some communication "algorithms" in a network language (NDLII on Burroughs (Unisys)) that not only lacked "goto" but also *any* way to break out of a loop short of setting a boolean variable, testing it and conditionally executing or not the next block of code.

Regards!

...JRF...

Re: goto command in shell

Jeff Schussele — Wed, 22 May 2002 14:59:05 GMT

Hi andi,

As Paula stated you can call another script from w/in a script - but keep in mind you cannot go back. And don't try to call back to the org script or you'll be in loop hell as it would go back to the start of the org script & hit the call, which hits the call in 2nd script, etc.

Rgds,
Jeff

Re: goto command in shell

Tom Danzig — Wed, 22 May 2002 18:20:04 GMT

There is a goto in csh. Not recommended though. It's thought to be poor programming practice.

Re: goto command in shell

James R. Ferguson — Wed, 22 May 2002 18:23:20 GMT

Hi:

...and the 'csh' is a poor practice shell... :-))

...JRF...

Re: goto command in shell

Ed Sampson — Thu, 23 May 2002 13:20:44 GMT

One good way to branch to different logic is the case statement. An example can be found in the accounting script /usr/lib/acct/runacct.
It uses the case statement to restart accounting is if fails partway through the processing.