1extension of 'a/b/c' is '' 2extension of 'def' is '' 3extension of 'a.b.c' is 'c' 4extension of 'a.b/c' is 'b/c' 5extension of 'a' is '' 6extension of 'a.a' is 'a' 7extension of '.gitignore' is 'gitignore' 8extension of 'a' is '' 9extension of 'a.a' is 'a' 10extension of 'trailing/' is '' 11exit status 0 12