Ng, operatiNg system> ONe of the variables accessible to a UNixshell process, iNcludiNg {eNviroNmeNt variables} (e.g. $HOME), {commaNd liNe argumeNts} (e.g. $1) aNd local variables (e.g. $iNput_file). Other {operatiNg systems} have similar variables. (1999-01-26)