vi/vim navigation — scroll half a page backward (up) In vi/vim normal mode, which control-key command scrolls the screen up by half a page (i.e., a half-page backward)?

Introduction / Context:
Beyond single-line cursor moves, vi/vim provides efficient paging commands to move through large files quickly. Knowing half-page and full-page scrolls is essential for rapid navigation without losing context.

Given Data / Assumptions:

• Editor is vi/vim in normal mode.
• We need the half-page scroll upward (backward through the file).
• Default key bindings are in effect.

Concept / Approach:

In vi/vim, Ctrl+U scrolls upward by half a screen (half a page). Its opposite is Ctrl+D, which scrolls downward by half a screen. Full-page equivalents are Ctrl+B (back) and Ctrl+F (forward). These scrolling commands move the window while keeping the cursor in view.

Step-by-Step Solution:

Verification / Alternative check:

Open a long file, note the line numbers on the screen, press Ctrl+U, and observe that the topmost line advances toward lower numbers by roughly half the window height. Repeat with Ctrl+D to confirm symmetry.

Why Other Options Are Wrong:

• [Control-d]: scrolls half a page down (forward), not up.
• [Control-c]: interrupts operations in many shells/contexts, not a vi scroll.
• [Control -P]: not a standard vi paging command; in insert mode Ctrl+P may complete words in vim but does not scroll.
• None of the above: incorrect because Ctrl+U is correct.

Common Pitfalls:

Confusing Ctrl+U with undo (u); mixing up half-page commands (Ctrl+U vs Ctrl+D); forgetting that these are view scrolls and do not change file content.

Final Answer:

[Control - u]