| Name | Type | Description |
| ADDON | noun | path to addons |
| ARGV | noun | command line |
| CONFIG | noun | path to user configuration files |
| FIXFONT | noun | fixed space font (used in session windows) |
| IFCONSOLE | noun | if a console front end |
| IFJAVA | noun | if a Java front end |
| IFUNIX | noun | if UNIX |
| IFWINCE | noun | if Windows CE |
| IFWINNT | noun | if Windows NT,2000,XP |
| IFWIN32 | noun | if Windows (9x,ME,NT,2000,XP) |
| jaddonpath | verb | adds path to addons |
| jconfigpath | verb | adds path to user configuration files |
| jhostpath | verb | converts path name to use host path separator |
| jsystemdefs | verb | loads appropriate netdefs or hostdefs |
| jsystempath | verb | adds path to J system directory |
| jtemppath | verb | adds path to directory for temporary files |
| juserpath | verb | adds path to user's directory |
| JIJX | noun | 1 if -jijx parameter (i.e. don't create ijx window) |
| PROFILE | noun | name of profile file |
| PROFONT | noun | proportional font (used in forms) |
| SYSTEM | noun | path to J system directory |
| TEMP | noun | path to temporary directory for temporary files |
| UNAME | noun | name of UNIX o/s |
| USER | noun | path to user's directory |