Support

Hi David-Andrew,

First, you seem to be using the PHP CGI instead of the PHP CLI interface. If unsure, run /path/to/php -v and look at the output. It should read something like:

PHP 5.3.4 (cli) (built: Dec 15 2010 12:15:07)

Not the "(cli)" part. If it reads cgi, FastCGI or fcgi it's not the binary you want.

If you do use the PHP CGI binary, the -q and -f options are not required. In this case the command line can be written as

/path/to/php /path/to/backup.php -profile=4 >/dev/null 2>&1

This is how I've set up this and other sites' automated backups ;)

It's "unixese" :) Linux, like all UNIX derivatives, defines two output streams: standard output (1) and error (2). The single greater-than sign redirects the default stream, the standard output. Thus, > /dev/null means that the standard output is redirected to the UNIX equivalent of a black hole. This leaves us with a problem. The error stream is still output and, in the case of CRON, will trigger an email with the error message. Therefore, in order to avoid that, you need to redirect the error stream to the bit bucket (/dev/null). The redirection operator can take an optional argument, telling it which output stream to redirect, just by prefixing it with the output stream's number. As a result, we have two choices:
1. Write 2>/dev/null which means "redirect output stream 2 (error) to /dev/null; or
2. Write 2>&1 which means "redirect output stream 2 (error) to output stream 1 (standard output)". Since the standard output is already redirected to /dev/null, the second stream goes to the first stream which goes to /dev/null.

Now, if you were a UNIX geek, which of the two would you use? The first one is too obvious and non-geeks can understand it. Therefore the standard practise is to use the second form which is very obscure, uses less characters and gives you that awe-inspiring geekiness points. Little wonder why it's stuck with us and everyone's using it, despite not realizing why exactly it works :D

PS: It took me a few years to realize what on Earth this line-noise-looking four character combo is supposed to really do. I only found out by accident, while searching for a completely different thing.