Question about System call

[rvpals]

My problem is that web host said there is a program /usr/bin/convert I can use to convert image files, after I call it in my code, it does not seemed to be doing anything. I'm sure the command line is right because I echo the commandline to make sure.

How do I make sure that an external program does actually exists?

I use if (file_exists("/usr/bin/convert")), is there any othe way? Or am I doing something wrong that the system call is not working?

For example:

//convert test.jpg to converted.jpg
$command = "/usr/bin/convert \"test.jpg\" \"converted.jpg\"";

echo $command;

system($command);

[bradgrafelman]

Do you have shell access (i.e. SSH, telnet, etc.) to the host? If so, try running the command yourself from the shell and see what happens.

Also, try using [man]passthru()[/man] so that we can see the output of the command. Maybe it's spitting out an error message that could help us debug!

[rvpals]

Originally posted by rvpals
My problem is that web host said there is a program /usr/bin/convert I can use to convert image files, after I call it in my code, it does not seemed to be doing anything. I'm sure the command line is right because I echo the commandline to make sure.

How do I make sure that an external program does actually exists?

I use if (file_exists("/usr/bin/convert")), is there any othe way? Or am I doing something wrong that the system call is not working?


For example:

//convert test.jpg to converted.jpg
$command = "/usr/bin/convert \"test.jpg\" \"converted.jpg\"";

echo $command;

system($command);

Thanks for the reply. I will try it and see what happen. I don't have shell access.

Is it good enough to use file_exists to determine if I have access to the /usr/bin/convert?

[bradgrafelman]

Not really... try [man]is_readable/man