7.4 What Can Go Wrong?


Many of the errors that can occur with CGI programs produce a page displayed in the browser as shown in Figure 7.6. Pretty helpful, huh?

Figure 7.6. Server error

graphics/07fig06.gif

There could be many causes of this condition. The following are some common things to check.

  • The script is syntactically incorrect (try perl -c script.cgi ).

  • The first line is not #!/usr/bin/perl .

  • There are incorrect file permissions (try chmod a+rx script.cgi or ls-l ).

  • There are incorrect directory permissions (be sure the cgi-bin directory has 755 permissions).

You can also run the program from the command line:

 $  ./error.cgi  syntax error at ./error.cgi line 6, near ") chomp"  Execution of ./error.cgi aborted due to compilation errors. 

A clue! The script has a syntax error near line 6.

When all else fails, check the error log file /var/log/httpd/error_log . You might see a line that looks like this:

 syntax error at /var/www/cgi-bin/error.cgi line 6, near ") chomp"  Execution of /var/www/cgi-bin/error.cgi aborted due to compilation  errors. [Fri Mar 25 10:23:17 2002] [error] [client 127.0.0.1] Premature  end of script headers: /var/www/cgi-bin/error.cgi 

Aha! Another clue pointing to line 6!



Open Source Development with Lamp
Open Source Development with LAMP: Using Linux, Apache, MySQL, Perl, and PHP
ISBN: 020177061X
EAN: 2147483647
Year: 2002
Pages: 136

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