There are four options to compare S3 files and local files:
Select Advanced -> Comparer option from Tools menu.
Select object(s) on S3 to be compared with local files and right click, then select “Select Right Side to Compare” option. Now select file(s)/ folder(s) on left panel, right click on them and select “Comparer to #S3 file/folder name#”
Select and right click on bucket whose object you want to compare and choose “Select Right Side to Compare” option. Now select file(s)/ folder(s) on left panel, right click on them and select “Comparer to #bucket name#”
Select and right click on file(s) and folder(s) on local file panel and choose “Select Left Side to Compare” then select and right click on S3 bucket or object and choose “Compare to ##”
Using any of the above four options, you will be seen a comparer window. On comparer window there are options available to compare the contents of local file(s) and S3 file(s).
Click
Compare Amazon S3 files with local files and folders
to know more about comparer.