BUGS
A recursive login, as used to be possible in the good old days, no longer works; for most purposes
su(1) is a satisfactory substitute. Indeed, for security reasons,logindoes avhangup()system call to remove any possible listening processes on the tty. This is to avoid password sniffing. If one uses the commandlogin, then the surrounding shell gets killed byvhangup()because it's no longer the true owner of the tty. This can be avoided by usingexec loginin a top-level shell orxterm.