In Finder, press Command + Shift + .
In Finder, open the folder you want to check and press Command + Shift + .
In Terminal, run: defaults write com.apple.finder AppleShowAllFiles -bool true
In Terminal, run: killall Finder
In Finder, press Command + Shift + . again to toggle hidden files off
In Terminal, run: ls -la to list hidden files in a directory
In Finder, use Go > Go to Folder and enter the path to a hidden file or folder
In Finder, check the user Library folder by holding Option and selecting Go > Library