I have html files/Directories, I want to convert them to .chm help file, under Linux using command lines at Terminal?
Any help would be appreciated.
The Free Pascal compiler, version 2.4.4 or higher has a CHM compiler for *nix called "chmcmd". I would recommend getting it from version 2.6.0. It works on MSHelp .hhp project files.
The compiler is also available in source (styled like a classes library), so you could roll your own. It is crossplatform, but Big Endian platforms are not tested very well.
2.6.0 is from januari 1st 2012, so you might need to get it from a "bleeding edge" packages repository of your distribution.