Isn't the >> going to cause urls.txt to grow geometrically? eg, copying http://example.com/foo http://example.com/foo and then http://example.com/bar http://ex

Isn't the >> going to cause urls.txt to grow geometrically? eg, copying http://example.com/foo http://example.com/foo and then http://example.com/bar http://example.com/bar and then http://example.com/baz http://example.com/baz I think urls.txt would look like: http://example.com/foo http://example.com/foo http://example.com/bar http://example.com/foo http://example.com/bar http://example.com/baz EDIT: I stand corrected. I should have run the code instead of mentally executing it. One issue I did find when I ran it. The shebang should be: #!/bin/bash as [[ is a bash built-in. I'm on Ubuntu - maybe this works on Mac as /bin/sh is an alias to /bin/bash?