.gitignore to ignore everything aside from files with certain extensions in nested subdirectories associated with some top level subdirectories

Question

I would like for git to ignore all files except those with a few different extensions buried somewhere within a specific set of subdirectories.

For examples, say I have a directory with the following sub-directories:

subdir1
subdir2
subdir3
subdir4
subdir5
...

Each subdirectory contains an arbitrary number of nested sub-directories. Files with extension .txt or .pdf may be present in some of those nested sub-directories. I would like to have the repo track only the .txt and .pdf files somewhere within subdir2 and subdir3 and no other files.

Please explain why your solution works.

Answer 1

If you want to ignore ALL files expect all .pdf and .txt files in the directory subdir2/ and subdir3/, add following to gitignore:

# Ignore everything
*
!*/

# But not these files
!.gitignore
!subdir2/**/*.pdf
!subdir2/**/*.txt
!subdir3/**/*.pdf
!subdir3/**/*.txt

subdir/** matches all files and directories in any subdir/ directory and all of its subdirectories. The ! negates the pattern where follows. And so you can ignore all except the .pdf and .txt files in the wished directories.

The folder-structure is as follow:

|-- folder
    |-- .git
    |-- .gitignore
    |-- subdir1/
        |-- <folder content>
    |-- subdir2/
        |-- <folder content>
    |-- subdir3/
        |-- <folder content>
    |-- subdir4/
        |-- <folder content>
    |-- subdir5/
        |-- <folder content>