pwd, pbd – working directory
prints the path name of the working (current) directory.
is guaranteed to return the same path that was used to
enter the directory.
If, however, the name space has changed, or directory names
have been changed, this path name may no longer be valid.
for a description of
prints the base name of the working (current) directory.
It prints no final newline and is intended for applications
such as constructing shell prompts.