gitignore binary files that have no extension

Question

How can binary files be ignored in git using the .gitignore file?

Example:

$ g++ hello.c -o hello

The

Answer 1

The .gitignore mechanism works only based on file names, not on file contents. Being a binary file is a property of the content, hence you can't ask git ignore binary files directly, but only to ignore them by name (and as other suggested, you can either add all binary file names to your .gitignore or use an appropriate naming convention).

The fact that .gitignore works on file names is an important property performance-wise: Git only needs to list files, but not to open and read them to know which files to ignore. In other words, Git would be terribly slow if you could ask it to ignore files based on their contents.