System.Environment.Blank

Copyright	(c) Habib Alamin 2017
License	BSD-style (see the file libraries/base/LICENSE)
Maintainer	[email protected]
Stability	provisional
Portability	portable
Safe Haskell	Safe
Language	Haskell2010

getExecutablePath :: IO FilePath Source

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.)

Since base 4.11.0.0, getExecutablePath resolves symlinks on Windows. If an executable is launched through a symlink, getExecutablePath returns the absolute path of the original executable.

Since: base-4.6.0.0

getArgs :: IO [String] Source

Computation getArgs returns a list of the program's command line arguments (not including the program name).

getProgName :: IO String Source

Computation getProgName returns the name of the program as it was invoked.

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.

withArgs :: [String] -> IO a -> IO a Source

withArgs args act - while executing action act, have getArgs return args.

withProgName :: String -> IO a -> IO a Source

withProgName name act - while executing action act, have getProgName return name.

getEnvironment :: IO [(String, String)] Source

getEnvironment retrieves the entire environment as a list of (key,value) pairs.

If an environment entry does not contain an '=' character, the key is the whole entry and the value is the empty string.

getEnv :: String -> IO (Maybe String) Source

Similar to lookupEnv.

getEnvDefault Source

Get an environment value or a default value.

setEnv Source

Like setEnv, but allows blank environment values and mimics the function signature of setEnv from the unix package.

unsetEnv :: String -> IO () Source

Like unsetEnv, but allows for the removal of blank environment variables. May throw an exception if the underlying platform doesn't support unsetting of environment variables.