using system(); to run a prescibed command 4

[charlesy]

I am trying to use the system(); command to execute this<br>system('echo &quot;FRPO R3, 01; FRPO L1, $currentL1; FRPO L2, $currentL2; FRPO L3, $c<br>urrentL3; FRPO L4, $currentL4; FRPO R3 00;&quot; ¦ lp -d PR0_KYO -o nobanner');<br><br>These characters tell a Kyocera printer some alignment information.<br><br>It looks like this running from the prompt<br>echo &quot;FRPO R3, 01; FRPO L1, 01; FRPO L2, 00; FRPO L3, 01; FRPO L4, 25; FRPO R3 00;&quot; ¦ lp -d PR0_KYO -o nobanner<br><br>I cannot seem to be able to tell the system()<br>function that what is between the '' is the command to send to the shell but then have the printer understand that what is in the &quot;&quot; is the pre-scribed command<br><br>much obliged

 

[Octalman]

The 'single-quotes'(apostrophes) prevent evaluation of $currentLn's, so they are passed to the printer as-is.&nbsp;&nbsp;You will have to use only &quot;double-quotes&quot; for this.<br>

 

[MikeLacey]

like this<br><br><FONT FACE=monospace><b><br>system(&quot;echo \&quot;FRPO R3, 01; FRPO L1, $currentL1; FRPO L2, $currentL2; FRPO L3, $currentL3; FRPO L4, $currentL4; FRPO R3 00;\&quot; ¦ lp -d PR0_KYO -o nobanner&quot;<br></font></b><br><br> <p>Mike<br><a href=mailto:Mike_Lacey@Cargill.Com>Mike_Lacey@Cargill.Com</a><br><a href=

http://www.cargill.com/>

Cargill's Corporate Web Site</a><br>

 

[is1]

Hello
I have a problem regarding perl5 the installation , and perl5 run the program .
I have a windows ME and I am how s the install the perl5 and give suggestion the how’s the program run.

 

[is1]

Hello
I have a problem regarding perl5 the installation , and perl5 run the program .
I have a windows ME and I am how s the install the perl5 and give suggestion the how’s the program run.
mail to me (prem12july@hotmail.com)...

 

[MikeLacey]

hello is1

If you go to

http://www.activestate.com

you can download the Perl installation for free.

You may well need to install the new version of windows installer first (MSI) and this is well worth doing.
Mike
________________________________________________________________________________

&quot;Experience is the comb that Nature gives us, after we are bald.&quot;

Is that a haiku?
I never could get the hang
of writing those things.

 

[Coderifous]

And by the way: get rid of Windows ME. I have it at home and I can't stand it. It's the most pathetic OS ever. EVER!!!!!! I have to reboot several times an evening if I'm debugging a Perl script. I HATE IT! Moving to Linux soon.

Oh and uh, Mike, why didn't you direct that poor young man to use the qq// operator?

system(qq/echo &quot;FRPO R3, 01; FRPO L1, $currentL1; FRPO L2, $currentL2; FRPO L3, $currentL3; FRPO L4, $currentL4; FRPO R3 00;&quot; ¦ lp -d PR0_KYO -o nobanner/);

It's much more useful in the long run to choose your own quotes!

Hey Mike: know anything about Ruby?

--jim

 

[MikeLacey]

I don't like qq//, I think it's a bit naff..... In fact, that's the first time I've ever typed it - probably the last as well.

Ruby: No, I don't sorry. It seems to be well thought of though; from comments on perl5-porters it was one of the things that irritated people enough to get started on Perl6. Mike
________________________________________________________________________________

&quot;Experience is the comb that Nature gives us, after we are bald.&quot;

Is that a haiku?
I never could get the hang
of writing those things.

 

[goliath]

Is there a way to capture any error codes resulting from using they system() command?

 

[Coderifous]

If I was you I'd not use the system() function, and use the back-ticks (graves-accents) instead. They execute their contents as from the command line, and return a list which is the resulting output from the system.

Example:
@directory_listing = `ls -l`;

That's what I normally do when I care about capturing output.

--jim

 

[Haunter]

You can use the eval function to catch errors

eval {
system(qq/echo &quot;FRPO R3, 01; FRPO L1, $currentL1; FRPO L2, $currentL2; FRPO L3, $currentL3; FRPO L4, $currentL4; FRPO R3 00;&quot; ¦ lp -d PR0_KYO -o nobanner/);
}
#Eval dumps error to this var $@
if ($@){ send error message or jump to some other action

}

Never tried this on a system call but should work

 

[svar]

No, eval does not work here, I think because as far as perl goes, the system command executed ok. Instead you should
try:
my $return_code= 0xfff & system (&quot;$systemcommand&quot;
$return_code=0 is no error. You can look up the rest of the story in teh Camel book, p. 230

svar