How do version control systems figure the different between 2 version of a file

[gayathri hariharan]

Hello Author,

I'm new to version control and so my questions might be basic.
If i make changes to a text file say hello.txt , then its probably easier to figure the changes to the file.
If i check in a pdf document how would the version control figure the changes. Do they ship with tools to check changes across different types of document?

[Steven Bell]

On all the Version Control Systems I've used if the file is not plain text (.txt, .java, .c, .bat, ect...) it sees the file as binary. A changed binary file simply replaces the old one.

[Jeff Machols]

Subversion can only diff text files at the moment. You can do a binary diff to apply changes/patches to binary files. If there is a tool that can show the content differences of PDFs, subversion allows you to call external programs to perform the actual diff.