Quickly compare two CSV files with Powershell

You can use Powershell to quickly compare two CSV files, and to see which records exist in file A, but not in file B (or vice versa).

We will use the two CSV files below as an example. Note: it is required that records in both files are sorted.

Run “diff” tool via Powershell

1. Open up a new Powershell window.
2. Navigate to the directory that contains the 2 CSV files.
3. Run this command:
   diff (cat file1.csv) (cat file2.csv)
4. This will give the following output:

InputObject SideIndicator
----------- -------------
record4     <=

The output above indicates that the line “record4” exists in file1.csv, but not in file2.csv.