You say you want a Batch file, but are you really looking for an Excel macro.
If it is a macro using Visual Basic for Applications, running within Excel, then this is the right forum.
If it is a macro you want then you are going to have to include a lot more information -
1. What rows are you copying,
2. How are those rows selected - do they have certain values in specific cells
3. Are you expecting to open a series of workbooks automatically or are you copying from one open workbook.
4. Where do the copied rows go in Merged.xls. Do they go to "Sheet1" or another worksheet,
5. Are copied rows always copied to the same worksheet
6. Is each set of copied rows just copied below existing rows of data.
6. Are there any issues with duplicate data