What distro are you running? My Debian automagically installed it to /usr/games/stockfish
SCID vs PC(Linux)

Get the latest binary which is sutable for your system from here:
Then put the binary "somewhere", probably to a system PATH like /usr/local/bin
Copying files at a system folder needs sudo/admin rights, but every system user should be able to use the engine. Else, just leave it somewhere under your /home/CleverMaverick userdir.
Make the binary executable:
sudo chmod +x /usr/local/bin/stockf*
(or wherever the binary is located- sudo not needed for local installation).
Then just point scidvspc to the binary, configure it and you're ready to go.
Oh, yes! Linux executable binaries have no suffix like .exe, .bat or anything.
Why not get the binaries from here?
I'm trying to add Stockfish 6 as a new analysis engine in my SCID vs PC but the problem is I get this message "The analysis engine terminated without exit code:""" What file should I place in the command? What I only know is in Windows, one must find the .exe file. How about in Linux, what should I place?