I've made three text files: 0nl.txt, 1nl.txt and 2nl.txt.

They both have the same content:


The only difference between them is how many newlines they have after the final 'o', with 0, 1 and 2 respectively.

I can compare between the files using FC:

C:\Users\NeatN\Desktop\fctest>fc 0nl.txt 1nl.txt
Comparing files 0nl.txt and 1NL.TXT
FC: no differences encountered

C:\Users\NeatN\Desktop\fctest>fc 0nl.txt 2nl.txt
Comparing files 0nl.txt and 2NL.TXT
***** 0nl.txt
***** 2NL.TXT


C:\Users\NeatN\Desktop\fctest>fc 1nl.txt 2nl.txt
Comparing files 1nl.txt and 2NL.TXT
***** 1nl.txt
***** 2NL.TXT


COMP, on the other hand, detects that they have different sizes but doesn't show the differences between them:

C:\Users\NeatN\Desktop\fctest>comp 0nl.txt 1nl.txt /M
Comparing 0nl.txt and 1nl.txt...
Files are different sizes.

C:\Users\NeatN\Desktop\fctest>comp 0nl.txt 2nl.txt /M
Comparing 0nl.txt and 2nl.txt...
Files are different sizes.

C:\Users\NeatN\Desktop\fctest>comp 1nl.txt 2nl.txt /M
Comparing 1nl.txt and 2nl.txt...
Files are different sizes.

How do I detect the missing newline in 0nl.txt compared to 1nl.txt, and show it to the user?


You may use fc /n. The /n parameter is described as :

/N    Display line numbers during an ASCII comparison.

This would look on comparison like this :


  • This doesn't do what I need: FC still ignores the missing newline in 0nl.txt. – NeatNit Nov 3 '18 at 17:46
  • Is the problem that the newlines are Linux type line-feeds rather than Windows type carriage-return/line-feeds? Could you post these two files? – harrymc Nov 3 '18 at 18:08
  • No, they were all made with notepad. I managed to figure it out, see my own answer - maybe that will clarify what I meant. – NeatNit Nov 3 '18 at 18:20

I solved it with the following code:

FC /B 0nl.txt 1nl.txt > NUL
    ECHO TEST FAILED - output doesn't match
    FC /N 0nl.txt 1nl.txt
    IF !ERRORLEVEL! EQU 0 ECHO There is a missing or extra newline character ^(\n^) at the end of the file

Essentially, I do a binary comparison first, and if that fails then there must be a difference. If an ASCII comparison passes later, then the difference must be in the final newline.

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