ghci
The Glasgow Haskell Compiler's interactive environment.
TLDR
Start a REPL (interactive shell)
$ ghci
Start a REPL and load the specified Haskell source file
$ ghci [source_file.hs]
Start a REPL and enable a language option
$ ghci -X[language_option]
Start a REPL and enable some level of compiler warnings (e.g. all or compact)
$ ghci -W[warning_level]
Start a REPL with a colon-separated list of directories for finding source files
$ ghci -i[path/to/directory1]:[path/to/directory2]
