A URL can be used to download data from a URL to the specified file.
Each call of a tool service works within its own specially created sub-directory of a directory specified by the location. When data is written to a file, the file is within the sub-directory for that call.
In the following example the data from http://www.myexperiment.org/files/534/download/addthem.sh is written to the file addthem.sh.
The command is sh addthem.sh First_number number2.txt
You can remove a URL by clicking the Remove button to the lower right of its area. This will prevent downloading form the URL and remove writing to the specified file.
You can add a URL by clicking the Add URL button.