If you don't have El-Get installed, first install it. After that, place the following command in your init file and restart your Emacs.

(el-get-bundle tarao/el-get-lock)

To enable version locks for all packages, run el-get-lock command without an argument. This can be done by M-x el-get-lock or placing the following code in your init file.

(el-get-lock)

If you want to lock only a few packages, then pass them to el-get-lock command. You can use the command multiple times. (All the packages passed to the command are marked as locked.)

(el-get-lock 'evil 'anything)
(el-get-lock 'magit)

You can also specify packages not to lock by el-get-lock-unlock command.

(el-get-lock)
(el-get-lock-unlock 'undo-tree)

Note that el-get-lock or el-get-lock-unlock without an argument resets the locked/unlocked package list and marks all the packages as locked/unlocked respectively.

If a package is marked as locked, a new installation of the package by El-Get will be locked to a version which is registered in a lock file (~/.emacs.d/el-get.lock). If there is no version registered, the latest version is installed and the version is registered to the lock file.

Assume that you have already run el-get-lock by hand or in your init file. After that, el-get-install or el-get-update will automatically maintain the lock file but if you have packages already installed before running el-get-lock, they need to be reinstalled or updated to get registered to the lock file. M-x el-get-reinstall, M-x el-get-update, or M-x el-get-update-all does this for you.

The lock file is ~/.emacs.d/el-get.lock by default and customizable by el-get-lock-file variable. It is good to have the lock file version controlled by for example the following list of commands, which is for git.

cd ~/.emacs.d/
git add el-get.lock
git commit -m 'Add el-get lock file.'

When you restore the installation of packages by el-get function written in your init file, they are locked as long as your init file properly initializes el-get-lock as described above.

If you have packages already installed by el-get before using el-get-lock and the initialization of el-get-lock and its lock file comes from another machine (via git pull-ing your configuration for example), you need to synchronize your installed packages to locked versions by M-x el-get-lock-checkout. In this case, neither el-get-update nor el-get-update-all is suitable since they may update your package to a newer version than the locked version.

M-x el-get-update or M-x el-get-update-all will update your packages as usual. After that, you will see that your version controlled lock file have been changed. If the updated versions work fine, then commit your lock file.

cd ~/.emacs.d/
git add el-get.lcok
git commit -m 'Update some packages.'

If an updated package breaks your environment and you want it to revert, then revert the lock file first. This will cancel registering the updated versions.

cd ~/.emacs.d/
# This will revert the entire update; you may need to manually modify
# the lock file if you have multiple packages updated and not all of
# them are to revert
git checkout el-get.lock

Then, revert the packages by M-x el-get-lock-checkout and now you have versions before the update.

These types are fully supported. Packages of these types can be locked, updated and reverted.

• git
• github
• emacsmirror
• hg

These types are partially supported. Packages of these types can be locked and updated but cannot be reverted. If you try to revert the package by el-get-lock-checkout, the package is simply reinstalled, i.e., the latest version from a remote host get installed.

• http
• ftp
• emacswiki

Note that the first locked installation for a package of these types yields an error when the remote version gets newer than the locked version. The only way to get rid of the error is to accept the latest version by el-get-reinstall.

• el-get-lock-file : file

  File to store the information of previously installed versions.

• el-get-lock (packages)

  Lock El-Get repository versions of packages.

  If packages are specified, those packages are marked to be locked. Otherwise, the all installed packages and packages to be installed in future are locked.

  Packages marked as locked and their dependent packages are locked to the version stored in el-get-lock-file. When el-get installs a package for the first time, the repository version is saved to el-get-lock-file. Next time you call el-get for the package, the repository version of the package is locked according to the value in the el-get-lock-file.

  Calling el-get-update for a package will change the stored value of el-get-lock-file to the latest version.

• el-get-lock-unlock (packages)

  Unlock El-Get repository versions of packages.

  If packages are specified, those packages are marked to be unlocked. Otherwise, the all installed packages are unlocked.

• el-get-lock-checkout (packages)

  Checkout the locked version of packages or simply the latest version is reinstalled for some unsupported package types.