# Installed Qt5 via the Qt website online installer,
# After downloading qt-opensource-linux-x64-1.6.0-4-online.run
# you (might) have to flip the eXecute bit before you can run it.
$ sudo chmod +x qt-opensource-linux-x64-1.6.0-4-online.run
$ sudo qt-opensource-linux-x64-1.6.0-4-online.run