demo program
............\multicopy
............\multicopy.bak
............\multicopy.c
............\multicopy.c.bak
............\scan
............\test1
............\test1.bak
............\test1.c
............\test1.c.bak
............\test2
............\test2.bak
............\test2.c
............\test2.c.bak
............\test3
............\test3.bak
............\test3.c
............\test3.c.bak