Symbolic links as a form of version control:
"ln -s mm-myversion.c mm.c" will link mm.c to mm-myversion.c. If mm.c already exists, this call will fail.

Debugging:
Use gdb to debug with watch commands. Watch is used to break execution of the program when a memory location is accessed. Can watch variables (watch x), watch memory locations pointed to (watch *p) or fixed addresses (watch *0x00401010).

3 types of watches: watch (breaks only on writes), rwatch (breaks only on reads), awatch (breaks on both reads and writes)