from the command prompt:
navigate to the directory (folder) containing your files to be renamed.
create the batch file like this:
copy con renameme.bat
ren 1.htm 1a.htm
ren 2.htm 1.htm
strike [enter] after each line
when done,
strike [ctrl]-z then [enter]
copy con means copy the output of the console
renameme.bat is the file that will be created
the other two lines will be added in turn to renameme.bat
the
[ctrl]-z key combination, when followed by the [enter] key tells the copy command that you are done, and writes the file to disk
then, from the command prompt, simply type
followed by the [enter] key
and, voila'! instant file rename!!