Registry DataBase : The \shell subkey
Just as a shell protects a content, a computer shell is a program acting between 2 levels : operating system and user. The operating system must be protected from the user and vice-versa. The user is asked to communicate with the operating system by using the shell. Thus, the shell is an environment which translates user commands into system functions. This shell also protects the user from the operating system's complexity by making it more human.
The \shell subkeys often have a \command subkey specifying an executable file which will perform the action corresponding to the context menu option. Between the \shell level and the \command level, you will see some of the following subkeys according to the type of associated action :
\config   Appears for example in the \scrfile subkey which contains screensaver data. The \command subkey contains a Default value of "%1", which indicates that the selected file is the one to execute.
\cplopen   Depends on the \cplfile subkey. Corresponds to \open for .cpl files.
\edit   Appears for example in the \batfile, \regfile and \txtfile subkeys. Enables opening those files in notepad. Indicate the program to execute for each file type.
\explore   Appears for example in the \Folder, \Inbox and \Microsoft Network subkeys. Enables opening the selected object in an Explorer window.
\find   Appears for example in the \My Computer, \Network Neighborhood, \Directory and \Drive subkeys. The \command subkey runs Explorer.exe and the \ddeexec subkey defines the routine included with Explorer.exe.
\install   Appears for example in the \inffile and \scrfile subkeys. Corresponds to the Install context menu option.
\open   Opens the file with the specified program.
\openas   Appears for example in the \Unknown subkey. When you try to open a file whose type has not been associated to an application, Windows opens the Open as dialog box where, you can select the default program for that file type.
\play   Appears for example in the \AudioCD and \AVIFile subkeys. The \command specifies CDPlayer.exe, MMPlayer.exe, etc. Remove the /close option at the end of the command line if you want to keep the program open after listening to or viewing the file.
\print   Loads the file in the program specified, prints it and closes the program.
\printto   When you drag and drop a file's icon on the printer icon, the printing job is handled by the \printto subkey if it exists, otherwise by the \print subkey.


© Franck Kiechel 2000-2001