I had a bunch of CSV files I needed to merge. I don’t spend half an hour loading all of them into Excel and doing a bunch of copying and pasting. Here’s how I merge CSV files from a command prompt.
copy /b file1.csv+file2.csv+file3.csv master.csv
That’s all there is to it. Load the resulting file into Excel, remove the duplicate header rows, and I have one big, master CSV file to work with in a matter of seconds. You can concatenate as few or as many files as you want this way. I happened to have 20, so this bit of command line trickery probably really did save me half an hour.