How can I split long commands over multiple lines in a batch file?
You can break up long lines with the caret ^
as long as you remember that the caret and the newline following it are completely removed. So, if there should be a space where you're breaking the line, include a space. (More on that below.)
Example:
copy file1.txt file2.txt
would be written as:
copy file1.txt^
file2.txt