CGI Tips and Tricks

CGI Tips and Tricks

When programming in CGI or any type of programming for that matter, there are strategies that will help you maximize your time.

Programmers CGI Editing Tips

Checking for Syntax Errors

If you make a change to a CGI script, and the script fails, determine any syntax error(s) in the script. To determine CGI/PL syntax errors, log in via SSH/Telnet and CD to the program directory and then run...

Perl yourscriptname.cgi or .pl

Based upon the error message(s), edit the script and re-upload.

One or Two Changes Only

Make only one or two changes and then send and test. Making too many changes at one time and then having a failed script will result in more lines of code to search through.

Reference Script - Two Scripts

Have a working script in one location and the script you are editing in a different location.  This way if the edited version fails, you can refer back to the original for reference if necessary.

Programming Backup Tips

Local Copies - backup_script.cgi

When editing any program, always make a backup on your local computer in the event the script fails.

Most programmers begin each day by making a copy so that they have reference points to return to in the event of problems.  For example...

backup_January01_02_scriptname.cgi
backup_January02_02_scriptname.cgi

Remote Copies - backup_script.cgi

If you have script.cgi located on your server, and you want to send an updated version, rename the script.cgi to backup_script.cgi.

Then simply upload the new file, chmod it if necessary, and run it.  In the event it fails and you are unable to determine why, you can always delete it the failed script and then rename backup_script.cgi to script.cgi.

Resend via FTP

By following the steps above, if the program fails, there shouldn't be any need to completely restore your entire site. Just resend via FTP the last working copy of the script.

Folder Backup versus Site Backup

While you can make a backup of your entire site, you can also backup just certain folders such as the cgi-bin.  This strategy saves you time by not having large backup files to download.  Plus, there is considerable risk of restoring an entire site when you consider your folder passwords, server files, etc.

For more details, review the steps to Backup Your Data.

mySQL

Please note that scripts can enter infinite loops and cause problems for any server.  Please edit scripts with care!

For additional assistance visit our CGI Troubleshooting page.