If you have need to rename any file in the Cisco flash then you can use the following
dir – to display list of files in flash
2 -rwx 8055040 Mar 1 1993 14:24:51 +00:00 c2960-lanbasek9-mz.122-50.SE1.bing
rename flash:c2960-lanbasek9-mz.122-50.SE1.bing c2960-lanbasek9-mz.122-50.SE1.bin
then confirm destination file
Destination filename [c2960-lanbasek9-mz.122-50.SE1.bin]?
once done .
2 -rwx 8055040 Mar 1 1993 14:24:51 +00:00 c2960-lanbasek9-mz.122-50.SE1.bin
We can see that the file has been renamed correctly.