Newbie Perl Help Please

**IDB** · 08-06-2004, 11:29 AM

I'm having the hardest time to get the simplest Perl script working.

I have a file called test.pl in my cgi-bin. It is CHMOD to 755

-rwxr-xr-x 1 errolian errolian 88 Aug 6 11:49 test.pl

The file is:

#!/usr/bin/perl
#
# Program to do the obvious
#
print 'Hello world.'; # Print a message

From a shell account (Putty) with Perl works fine:
jailshell-2.05a$ perl test.pl
Hello world.jailshell-2.05a$ perl test.pl

From a shell account (Putty) with no Perl prefix does not work:
jailshell-2.05a$ test.pl
jailshell: test.pl: command not found

In a web browser:
500 Internal Server Error

What am I doing wrong?

**Ron** · 08-06-2004, 11:53 AM

Ok, a few things...

first off is your $PATH... when you type
perl test.pl
Your "executables" path includes /usr/bin so perl ios found, and the perl filter looks in the current directory for the script.

However, when you just type
test.pl
Your "executables" path probably doesn't include your current directory.

If so, you'll need to type
./test.pl

#2) Look in your error log off of your control panel to give a clue as to what the internal server error is. With that script, it's likely that the error is a "premature ending of script headers" or some such. You need to have this at the very top of the script:
print "Content-type: text/html\n\n";

Good luck.

PS the script might also need to be in cgi-bin, but I'm not sure.
EDIT: I just re-read your post -- you already said it's in cgi-bin.

**jason** · 08-06-2004, 12:39 PM

As Ron siad, the root of your problem is that you aren't sending a Content-type header. Without that the server (and the receiving browser) don't know what kind of data is being sent and therefore don't know how to handle it. Just add

print "Content-type: text/html\n\n";

somewhere prefore the "Hello world" line.

--Jason

**Ron** · 08-06-2004, 01:01 PM

Hmmm, did I mistypoe something?

A clarification might be that the content-type printing ought to be somewhere after the #!/usr/bin/perl and probably after your beginning comments lines, but before any other lines that attempt to create output. I think that it's probably best to put it right near the top.

Also, you might want to consider making your shebang line to include the -w switch to help in some types of debugging:

#!/usr/bin/perl -w

Good luck! Let us know what happens.

**IDB** · 08-06-2004, 03:19 PM

Yep, content -type was indeed all I needed.

Thanks for all the help.

**Spathiphyllum** · 08-06-2004, 04:06 PM

Originally posted by IDB
Yep, content -type was indeed all I needed.

Thanks for all the help.

You also should be running in tainted mode:

Code:

#!/usr/bin/perl -T

use warnings; # instead of -w

# Program to do the obvious
#
print "Content-type: text/html\n\n";

my $message = 'Hello html-compliant world.';           # assign a variable message

print '<html><head><title>Hello world</title></head>'; # make it html compliant
print '<body><p>';
print "$message";                                      # print the message
print '</p></body>';
print '</html>';

I'm assuming that this script is intended for typical, html output?

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