Miscellaneous information about the system environment.
getArgs returns a list of the program's command
line arguments (not including the program name).
getProgName returns the name of the program as it was
However, this is hard-to-impossible to implement on some non-Unix
OSes, so instead, for maximum portability, we just return the leafname
of the program as invoked. Even then there are some differences
between platforms: on Windows, for example, a program invoked as foo
is probably really
FOO.EXE, and that is what
getProgName will return.
Returns the absolute pathname of the current executable.
Note that for scripts and interactive sessions, this is the path to the interpreter (e.g. ghci.)
Return the value of the environment variable
there is no such value.
For POSIX users, this is equivalent to