Since you have been given the " use File::Temp" speech, but not why, I will try to fill it in...

You have a race condition: application_1 and application_2, both using this code snippit, could come up with the same file name and both apps could attempt to use the temporary file. In the past, this code has led to root / administrator level exploits of systems.

File::Temp is yet another tool to help avoid this type of race condition.