[OpenSER-Users] tee with openser

Hi, This is probably a simple one - I have tried googling, but am not getting the answer to this. I am trying to catch what is displayed on screen and put it into a text file using tee so I can look at it. I can do 'free -h | tee dump.txt' and dump.txt is populated with data I can do 'asterisk -cvvvv | tee dump.txt' and dump.txt is populated with data when i try 'openser | tee dump.txt' and dump.txt does not get populated with the screen info. I have changed permissions to 666 on the dump.txt file incase that was the issue. Am I doing some silly? I thought that tee only copied what was displayed on screen. Thanks Robert