Those shell files are for removing junk of Xcode. 
Based on YoungSeon.Ahn's method  >> https://lovemewithoutall.github.io/it/xcode-clean-up/ << 
RemoveXcodeCache: 
~/Library/Developer/CoreSimulator/Devices 
~/Library/Developer/CoreSimulator/Caches/dyld 
~/Library/Developer/Xcode/DerivedData 
~/Library/Developer/Xcode/Archives 
~/Library/Developer/Xcode/iOS\ Device\ Logs  
RemoveSimulator: 
~/Library/Developer/Xcode/UserData/Previews 
Remove Caches: 
1. download the RemoveXcodeCache.sh file 
2. open the terminal 
3. chmod u+x RemoveXcodeCache.sh 
4. sudo ./RemoveXcodeCache.sh 
Remove Previews: 
1. download the RemoveSimulator.sh file 
2. open the terminal 
3. chmod u+x RemoveSimulator.sh 
4. sudo ./RemoveSimulator.sh
5. restart Xcode 
you should read the script line by line before you run it !!!!