*The ghc-mod command

?ghc-mod list
!Displays a list of modules
?ghc-mod lang
!Displays a list of language extensions
?ghc-mod flag
!Displays a list of GHC flags
?ghc-mod browse \[<package>:\]<module>
!Displays symbols of <module>
?ghc-mod check <HaskellFile>
!Checks syntax with GHC
?ghc-mod expand <HaskellFile>
!Expands Template Haskell
?ghc-mod debug <HaskellFile>
!Displays debug information
?ghc-mod info <HaskellFile> <module> <expression>
!Displays information about the expression
?ghc-mod type <HaskellFile> <module> <line-no> <column-no>
!Displays the types of all expressions including the expression
?ghc-mod find <symbol>
!Finds all module names exporting <symbol>
?ghc-mod lint <HaskellFile>
!Checks synstax with Hlint
?ghc-mod root <HaskellFile>
!Finds the root directory for the Haskell file
?ghc-mod doc <module>
!Finds the html document for the module
?ghc-mod boot
!Displays boot information for Emacs front-end
?ghc-mod version
!Displays the version of ghc-mod
?ghc-mod help
!Displays help messages

<module> for "info" and "type" is not used, anything is OK.
It is necessary to maintain backward compatibility.