Can anyone tell me how to write a PHP script to update this shell command?

/usr/local/psa/bin/domain.sh -u domain.com -passwd password

I am trying to update FTP passwords using a PHP script, in place of logging into Plesk everyday to change an FTP password. I have a web based tool that holds all my customers FTP info (UN, PW, etc...). I want to update my tool, then have it update the Plesk FTP password automatically using a PHP script with a shell command.

I don't exactly know how to do this ... but if the FTP login data for your shell command, or your shell command is held in any type of plain-text based file you should be able to do this easily enough.

If so, post the file and I'll take a look...

If not, good luck

try using
system ( string command [, int return_var])

If that doesn't work, you can use shell_exec. Here's a fun tutorial that uses it.

http://www.sitepoint.com/article/take-command-ajax/2