Final answer:
The correct keyboard shortcut to search forward in the command history is not listed among the provided options, but typically Ctrl + R is used to search backward, and the down arrow key or Ctrl + P can navigate through the history after initiating a reverse search.
Step-by-step explanation:
When working with the command line interface on Unix-based systems, such as Linux and macOS, the keyboard shortcut designed to search forward in the command history is usually Ctrl + R. However, none of the options provided in the question (Ctrl + F, Ctrl + B, Ctrl + G, Ctrl + H) serve that function. To clarify:
- Ctrl + R: Search backward through command history (reverse search)
- Ctrl + F: Move the cursor forward on the current line (Emacs binding in the shell)
- Ctrl + B: Move the cursor backward on the current line (Emacs binding in the shell)
- Ctrl + G: Exit the history search mode without executing a command (Emacs binding in the shell)
- Ctrl + H: Equivalent to backspace, deletes the character to the left of the cursor (Emacs binding in the shell)
Since the question specifically asks about searching forward in the command history, and given that the standard for reverse search is Ctrl + R, there is a possibility of confusion because by default there is no specific shortcut for forward-search history. Users generally navigate the command history forward by pressing the down arrow after searching backward or by pressing Ctrl + P to navigate up or down through the history in the shell environment.