Thanks to setlogin()/getlogin() some operating systems are frustratingly close to the point where all of the relevant information can be read straight out of th

Thanks to setlogin()/getlogin() some operating systems are frustratingly close to the point where all of the relevant information can be read straight out of the kernel's process table, without need for coöperatively maintaining a data file. On FreeBSD, for example, one can do everything except filter out the terminals where no-one is logged on yet and print a "FROM" column.