ghci: add page (#4576)

pages/common/ghci.md

@@ -0,0 +1,24 @@
+# ghci
+
+> The Glasgow Haskell Compiler's interactive environment.
+> More information: <https://downloads.haskell.org/ghc/latest/docs/html/users_guide/ghci.html>.
+
+- 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}}`