1)the command "dirname path" treats path as a pathnameand writes to the standard output the path prefix, that is everything up to but not including the last component. thus "dirname a/b/c/d" write a/b/c to standard output. If path is simple filename (has no / characters), then dirname writes a . to standard output. Implement "dirname" as a Korn Shell function. Make sure that it behaves sensibly when given values of path such as /.
2)implement the basename utility, which writes the last component of its pathname argument to standard output, as a Korn Shell function. For example
writes d to standard output.
3) The UNIX basename utility has an optional third argument. If you type suffix of path that is identical to suffix. For example