Linux C Line Hider - 26/08/2026 07:15 EDT

I want a lightweight, straight-C console tool that I can compile with a single
gcc call on both Ubuntu 26.04 LTS Server and Desktop.
When I launch it the program must:

• Prompt for the full path of the target text file (≈100 lines).
• Ask whether I intend to hide or unhide lines.
• Request how many lines to process (1–5).

In hide mode the utility must randomly choose that exact count of distinct line numbers (no manual picking) and make them invisible inside the file. In unhide mode it must put every previously hidden line back into its original position, effectively restoring the file exactly as it was.

If the chosen file already carries a set of hidden markers, the program should warn me and exit without touching anything—no merging or overwriting.

I also need:

• The .c source file, cleanly commented.
• A short README showing the gcc command (e.g., gcc -std=c11 -O2 linehider.c -o linehider) and a couple of usage examples.
• Any helper script or Makefile if you prefer.

Keep the solution portable, using only standard C and the usual GNU tools that ship with Ubuntu. Once I have the executable, I must be able to run it at will to hide or reveal lines as described.