Cd changes the current working directory to path_name. If you are not familiar with the concept of directories and path names, see "UNIX for Beginners" (Kernighan) and the description of the cd command in section 1 of the "UNIX User's Manual." Note that all subsequent commands that have filename arguments (for example, pdbrun, source, and write), are executed in the new working directory.
Example:
cd ../crodna