1 > Open Terminal
2 > defaults write com.apple.finder AppleShowAllFiles YES
3 >
Right-click on Finder while holding "Alt/option" key and select "Relaunch" the Finder.
To Hide
1 > Open terminal
2 > defaults write com.apple.finder AppleShowAllFiles NO
Please repeat above step 3> to relaunch the Finder.
Thank you.
I have found this solution here :
http://ianlunn.co.uk/articles/quickly-showhide-hidden-files-mac-os-x-mavericks/