Shell gets the file name under the specified directory

There are two directories A, B, two folders directory of some files are the same name, but the suffix is different, I want to a folder and B folder with the same file name of the files covered to B, and delete the name of B and different suffix file, many files

  #!/bin/bashfolder_a=/home/joe/test/afolder_b=/home/joe/test/bFor file_a in ${folder_a}/*;file_a_prefix=${file_a:%.*}file_prefix=${file_a_prefix#${folder_a}/*}#rm-F $FOLDER _b/${file_prefix}.*CP $file _a $FOLDER _b/ Done 

Shell gets the file name under the specified directory