PROC posix.exit (VAL INT exit.code)
PROC posix.getenv (VAL []BYTE envname, []BYTE value)
PROC posix.system (VAL []BYTE command, INT result)
PROC posix.read.file (VAL []BYTE filename, CHAN OF POSIX.FILE.LINE out)
PROC posix.read.pipe (VAL []BYTE command, CHAN OF POSIX.FILE.LINE out)
PROC posix.write.file (VAL []BYTE filename, CHAN OF POSIX.FILE.LINE in, CHAN OF POSIX.FILE.STATUS status, VAL BOOL append.to.end)
PROC posix.write.pipe (VAL []BYTE command, CHAN OF POSIX.FILE.LINE in, CHAN OF POSIX.FILE.STATUS status, VAL BOOL append.to.end)