unifdef is a small cli utility for removing c/c++ preprocessor conditionals from code, Linux kernel example:

$ unifdef -m -DCONFIG_SMP=y kernel/sched/*.[ch] include/linux/sched.h include/linux/sched/*.h

What a clever tool, it never crossed my mind to have a cli for this.

Sources:

• [1] https://linux.die.net/man/1/unifdef
• [2] https://lwn.net/ml/all/20250528085813.GX39944@noisy.programming.kicks-ass.net/
• [3] https://dotat.at/cgi/git/unifdef.git