Mercurial: The Definitive Guide

Chapter 5. Mercurial in Daily Use

Telling Mercurial Which Files to Track

Mercurial does not work with files in your repository unless you tell it to manage them. The hg status command will tell you which files Mercurial doesn’t know about; it uses a ? to display such files.

To tell Mercurial to track a file, use the hg add command. Once you have added a file, the entry in the output of hg status for that file changes from ? to A.

$ hg init add-example
$ cd add-example
$ echo a > myfile.txt
$ hg status
? myfile.txt
$ hg add myfile.txt
$ hg status
A myfile.txt
$ hg commit -m 'Added one file'
$ hg status

After you run a hg commit, the files that you added before the commit will no longer be listed in the output of hg status. The reason for this is that by default, hg status only tells you about “interesting” files—those that you have (for example) modified, removed, or renamed. If you have a repository that contains thousands of files, you will rarely want to know about files that Mercurial is tracking, but that have not changed. (You can still get this information; we’ll return to this later.)

Once you add a file, Mercurial doesn’t do anything with it immediately. Instead, it will take a snapshot of the file’s state the next time you perform a commit. It will then continue to track the changes you make to the file every time you commit, until you remove the file.

Explicit Versus Implicit File Naming

A useful behavior that Mercurial has is that if you pass the name of a directory to a command, ...