git add * (asterisk) vs git add . (period)

Question

I'm new to git and I have a question about adding files in git. I have found multiple stackoverflow questions about the difference between git add . and git add -a, git add --all, git add -A, etc. But I've been unable to find a place that explains what git add * does. I've even looked at the git add man page, but it didn't help. I've been using it in place of git add . and my co-worker asked me why. I didn't have an answer. I've just always used git add *.

Are git add . and git add * the same? Does one add changed files from the current directory only, while the other adds files from the current directory and subdirectories (recursively)?

There's a great chart listed on one of the other stack questions that shows the difference between git add -A git add . and git add -u, but it doesn't have git add *.

Note: I understand what it means to use the asterisk as a wildcard (add all files with a given extension). For example, git add *.html would add all files that have a .html extension (but ignore .css, .js, etc).

Thanks for the help!

Answer 1

add * means add all files in the current directory, except for files whose name begin with a dot. This is your shell functionality and Git only ever receives a list of files.

add . has no special meaning in your shell, and thus Git adds the entire directory recursively, which is almost the same, but including files whose names begin with a dot.

Answer 2

* is not part of git - it's a wildcard interpreted by the shell. * expands to all the files in the current directory, and is only then passed to git, which adds them all. . is the current directory itself, and git adding it will add it and the all the files under it.

Answer 3

Using the dot . in the shell usually means "the current directory".

When you use the asterisk * on a shell a feature called file-globbing is utilized. E.g. on bash the function glob() is doing just that. The manpage for glob (man 7 glob) states:

DESCRIPTION

Long ago, in UNIX V6, there was a program /etc/glob that would expand 
wildcard patterns.  Soon afterward this became a shell built-in.
These days there is also a library routine glob(3) that will perform this 
function for a user program.

Wildcard matching

A string is a wildcard pattern  if it contains one of the characters '?', '*' or '['. 

Globbing

Globbing is the operation that expands a wildcard pattern 
into the list of pathnames matching the pattern.

That means when you pass arguments to any program on the commandline that contain '?', '*'or '[', first globbing expands the wildcard pattern into a list of files and then gives these files as an argument to the program itself.

The difference in meaning between 'git add .' and 'git add *'is clearly described by Denis:

git add expects a list of files to be added. In the above example the shell expands * or . respectively and gives the result as a parameter to git add. Now the difference is that with git add . git will expand to the current directory whereas git add * triggers file globbing and such expands to all files and directories that do not start with a dot.

Answer 4

For clarity, I put the answer in the table below:

Additional notes (inspired by the @reka18 comment):

Note 1. git add -A and git add -u commands performed without additional parameters would be additional refinement (subdirectory or mask indication for the file name) work in the range of the entire working directory (also if we execute the command in the working subdirectory of the directory).

Note 2. The . and * are respectively the directory path (current directory) and the wildcard, which clarify the path of the command. For example, if the git add . or git add * command is executed in some subdirectory of a working directory, then their action is only used within this subdirectory, not the entire working directory.

Note 3. The git add -A and git add -u commands can be further refined by adding a path or mask for files, for example, git add -A app/controllers or git add -u app\styles\*.