How to eliminate the extra 0's in printing to html lines?

[cibalo]

Hello,

The following script produces two extra 0's at the end of the lines ---
see below.
#!/usr/bin/perl
print "Content-type: text/html\n\n";
print "# which sendmail<br>";
$out = system("which sendmail");
print "$out<br>\n";
print "<br>";
print "# which perl<br>";
$out = system("which perl");
print "$out<br>\n";
print "<br>";

And the browser displays as:
# which sendmail
/usr/sbin/sendmail 0

# which perl
/usr/bin/perl 0

Please help me to eliminate the two extra 0's at the end of the lines.
I have no idea where these 0's are coming from.

Thank you very much in advance!!!

 

[Bart Van der Donck]

The following script produces two extra 0's at the end of the lines ---
see below.
#!/usr/bin/perl
print "Content-type: text/html\n\n";
print "# which sendmail<br>";
$out = system("which sendmail");
print "$out<br>\n";
print "<br>";
print "# which perl<br>";
$out = system("which perl");
print "$out<br>\n";
print "<br>";

And the browser displays as:
# which sendmail
/usr/sbin/sendmail 0

# which perl
/usr/bin/perl 0

Please help me to eliminate the two extra 0's at the end of the lines.
I have no idea where these 0's are coming from.

I see the same results here. The problem is that you can't trust the
return value of the 'system'-command. The following should work:

$out = `which perl`;

 

[anno4000]

I see the same results here. The problem is that you can't trust the
return value of the 'system'-command.

You can trust it to be what it it supposed to be, but that is not the
output of the invoked command.

The following should work:

$out = `which perl`;

Read "perldoc -f system" with attention to the third paragraph to see
*why* this works.

Anno

 

[Jürgen Exner]

The following script produces two extra 0's at the end of the lines
--- see below.
#!/usr/bin/perl
print "Content-type: text/html\n\n";
print "# which sendmail<br>";
$out = system("which sendmail");
print "$out<br>\n";
print "<br>";
print "# which perl<br>";
$out = system("which perl");
print "$out<br>\n";
print "<br>";

And the browser displays as:
# which sendmail
/usr/sbin/sendmail 0

# which perl
/usr/bin/perl 0

That's exactly what should happen in this script.

Please help me to eliminate the two extra 0's at the end of the lines.
I have no idea where these 0's are coming from.

You are printing them ;-)
If you don't want to see the return value of your system() calls, then don't
print it, i.e. change
print "$out<br>\n";
to
print "<br>\n";

jue

 

[Sherm Pendley]

The following script produces two extra 0's at the end of the lines ---
see below.
#!/usr/bin/perl
print "Content-type: text/html\n\n";
print "# which sendmail<br>";
$out = system("which sendmail");
print "$out<br>\n";
print "<br>";
print "# which perl<br>";
$out = system("which perl");
print "$out<br>\n";
print "<br>";

And the browser displays as:
# which sendmail
/usr/sbin/sendmail 0

# which perl
/usr/bin/perl 0

Please help me to eliminate the two extra 0's at the end of the lines.
I have no idea where these 0's are coming from.

They're the value of $out when it's printed. System() does not do what you
think it does. For details have a look at the docs for the system() function:

perldoc -f system

sherm--

 

[A. Sinan Unur]

The problem is that you can't trust the
return value of the 'system'-command.

In what way does the return value of the system function match its
documentation?

perldoc -f system

Sinan

--
A. Sinan Unur <[email protected]>
(remove .invalid and reverse each component for email address)

comp.lang.perl.misc guidelines on the WWW:
http://augustmail.com/~tadmc/clpmisc/clpmisc_guidelines.html

 

[Ciba LO]

Hello Bart, Steffen, Anno, jue, sherm and Sinan!

Many thanks to you guys for replying to my post. Both the backquote
substitution and the omission of $out in the print statements are
working okayed to me.

Ciba

 

[Joe Smith]

I see the same results here. The problem is that you can't trust the
return value of the 'system'-command.

You most certainly _CAN_ trust the return value of the system() function.

The return value is documented, it's just not what you think it is.

if (system($command) == 0) {
print "The command '$command' executed with no errors\n";
} else {
warn "The command '$command' returned a non-zero error code: $?\n";
}

-Joe