I don't think that you can use RHC directly to get what you want.
- That may require an Request for Enhancement to be made to the RHC SCP command.
- File that here: https://github.com/openshift/rhc/issues
However you can use the following to find all of your GEARS:
rhc app show APP_NAME --gears | awk '{print $5}' | tail -n +3
From this list you can list all the logs for each gear that are part of that application.
for url in $(rhc app show APP_NAME --gears | awk '{print $5}' | tail -n +3); do for dir in $(ssh $url "ls -R | grep -i log.*:"); do echo -n $url:${dir%?}; echo; done; done
With that you can us simple scp commands to get the files you need from all of the gears:
for file_dir in $(for url in $(rhc app show APP_NAME --gears | awk '{print $5}' | tail -n +3); do for dir in $(ssh $url "ls -R | grep -i log.*:"); do echo -n $url:${dir%?}; echo; done; done); do scp "$file_dir/*" .; done