China DOS Union

I want to compare the contents of two text files and output the different content from the two files.
First I used

findstr /v /g:1.txt 2.txt>3.txt
pause

and it said findstr: the search string is too long

Both files are around 450K or so, and most of the content is the same, hehe

Then I used

for /f %%a in (1.txt) do (
for /f %%b in (2.txt) do (
findstr /v /c:"%%a" "%%b">>3.txt
)
)
pause

There was no error message this time, but 3.txt is an empty file. So depressing.......

Please give me some guidance, experts

The fc command is specifically for comparing files

Maybe you can give it a try

The text output by this command doesn't meet my requirements.... there is a lot of extra information. I only want to output the different content in the two files, and I need to use that content for something else...... still asking the experts for advice........

Comparing two text files over 450k in size, if you use that method and it actually works, it might still take several hours. The more different lines there are, the longer it will take.

A.txt

AAA
CCC
BBB

B.txt

BBB
AAA
CCC

Are the contents of a.txt and b.txt considered different or the same?

Consider them the same. Moderator, please help, many thanks

I couldn't solve it with DOS,
so later I wrote it in C. Anyone who knows, please leave a message, thanks.

To reduce runtime, my method is: use fc ---- delete duplicate lines ---- more +n, and the result is clean. Processing files around 450k generally takes a few dozen seconds.