Job Control: How to save output of background job in a variable

Using Bash in OSX. My script has these 2 lines: nfiles=$(rsync -auvh --stats --delete --progress --log-file="$SourceRoot/""CopyLog1.txt" "$SourceTx" "$Dest1Tx" | tee /dev/stderr | awk '/files transferred/{print $NF}') & nfiles2=$(rsync -auvh --stats --delete --progress --log-file="$SourceRoot/""CopyLog2.txt" "$SourceTx" "$Dest2Tx" | tee /dev/stderr | awk '/files transferred/{print $NF}') When I use the & after the first line (to run the two rsync commands in parallel), my later call to $nfiles returns nothing. Code: osascript -e 'display notification "'$nfiles' files transferred to MASTER," & return & "'$nfiles2' transferred to BACKUP," & return & "Log Files Created" with title "Copy Complete"' Can't figure out what's going on. I need the 2 rsyncs to run simultaneously.