[Bug-wget] agent-string and background

[5H]

Hi.
I need to download a file from a site that denies wget, so I changed 
the “agent-string” using the “-U” option. In this way I can download the 
file, but I have another problem now.
Using “-U” option wget works in background, but I need it does not because I 
use it inside a bash script that should wait the end of wget process.
How can I change the “agent-string” avoiding the background working mode?
Thank you very much.