Many Ubuntu distributions use dash as default for the shell.
I prefer the classic and more powerful bash.
Here a quick way to force the bash shell as default.
Open a terminal and execute this command :
$ sudo dpkg-reconfigure -plow dash
A message will appear indicating the default shell in use (it should say "dash", in this example is bash because I already executed the dpkg-reconfigure)
Done. From now on the bash shell is the default one for the user.