I am hosted with 1and1.com, and I have setup my files to be parsed with php5 using .htaccess.
But that only works in apache, and not in command line, wh
At least on Linux you can also specify the wanted PHP version in the first line of your script like so:
#!/usr/bin/php5.6
Make your script executable and specify the cron job in the following way:
# Just runs the script, which itself cares for the right php version
* * * * * root "/path/to/script.php"