I have encountered a strange issue in concatenating the files using the cat command. I have two files with one string in each of them:  file1:  ABCfile2:  DEFEither I do cat file1 file2 or I do cat file1 >> file2. I expect an output as shown below:  ABC  DEFHowever, I have a funny output like this:  ABCDEFI have checked the files and there is no extra space or characters. However, when I do manual deleting from the back of the string, I don't even see a single character. It works fine. I suppose there must be some kind of hidden character or line which I can't see.  It has been bugging me a lot because I have tons of files to concatenate. I can't do the same thing manually.  Any help is appreciated. 
Not able to cat a string from a file under a string of another file
cat;newlines