Emacs major mode to manage pacnew and pacsave files left by the pacman Arch tool
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UndeadKernel readme: add MELPA installation instructions
Some other misc clarifications
Latest commit 2854b87 Oct 18, 2018


Release tag MIT license


Emacs major mode to manage .pacnew and .pacsave files left by Arch's pacman. To merge files, pacfiles-mode automatically creates an Ediff merge session that a user can interact with. After finishing the Ediff merge session, pacfiles-mode cleans up the mess that Ediff leaves behind. pacfiles-mode also takes care of keeping the correct permissions of merged files, and requests passwords (with TRAMP) to act as root when needed.

pacfiles-mode is free software, licensed under the MIT License.

pacfiles-mode main interface

Installation and Setup

pacfiles-mode can be installed automatically from a package repository or manually.

Automatic installation

pacfiles-mode is in the MELPA package repository. To install from MELPA, make sure the following is somewhere in your ~/.emacs.d/init.el:

(require 'package)
(add-to-list 'package-archives '("melpa" . "https://melpa.org/packages/"))

Open emacs and execute M-x package-refresh-contents RET followed by M-x package-install RET pacfiles-mode RET. pacfiles-mode will then be compiled and installed.

Manual installation

To manually install pacfiles-mode, clone this repository into .emacs.d:

$ cd ~/.emacs.d
$ git clone https://github.com/UndeadKernel/pacfiles-mode.git

Then add the cloned folder to your load-path and require pacfiles-mode by adding the following to ~/.emacs.d/init.el:

(add-to-list 'load-path "~/.emacs.d/pacfiles-mode")
(require 'pacfiles-mode)


Start pacfiles-mode with the command pacfiles. Choose a file to merge by clicking (or pressing RET) on [merge]. An Ediff session will start; do not change the name of the Ediff buffers. After finishing the merging process, save the merged file (e.g., in Ediff's command buffer, use keybindings w c) without changing its name or location and quit Ediff. To apply the merge file to the file system, click (or press RET) on [apply]. Quit pacfiles-mode by pressing q.

Main interface

pacfiles-mode searches and lists all .pacnew and .pacsave update files found in /etc (by default). These update files can be discarded or, with the help of Ediff, compared or merged. Ediff is automatically setup for the user; permissions are also taken care for.

Pending files

.pacnew or .pacsave file that have not been merged by the user are shown under the pending header. Three actions are available on these files

Pending Actions

  • [merge]: start an Ediff session to merge the update
  • [diff]: compare the update with its base file
  • [delete]: delete the update and keep the base file as is

If the [diff] button is not available, there is no base file to compare with. In this case, [merge] will treat the update, as is, as the file to merge.

Merged files

.pacnew and .pacsave files that have been merged, but not applied into the file system, are shown under the merged header. Three actions are available on these files:

Merged Actions

  • [apply]: copy the merged file into the file system and delete the update file
  • [view]: show the merge of the update and its base file
  • [discard]: delete the merge file, keep the update file and the base file intact

Apply or discard all changes

Apply/Discard All Actions

The [Apply All] and [Discard All] buttons do what you would expect them to do.

Ediff tricks and tips

When merging an update, Ediff's setup will look like this:

Ediff interface

Ediff's control buffer (on the bottom) will be focused and ready to receive user commands. The following key bindings are most useful:

  • n / p: go to the next / previous place where there is a difference
  • a: place in the merge buffer the contents highlighted in the top left window (always the update file)
  • b: place in the merge buffer the contents highlighted in the top right window (always the base file to update)
  • w c: save the contents of the merge buffer
  • q: quit Ediff
  • ?: show Ediff's help

When saving the merge buffer, do not change the merge buffer's location or name. You can switch to the merge buffer, buffer C in Ediff, and modify it as any other buffer.

Functions and Variables of pacfiles-mode


  • pacfiles or pacfiles-start: start pacfiles-mode.
  • pacfiles-quit: quit pacfiles-mode.
  • pacfiles-revert-buffer: reload the list of update files

Configuration variables

  • pacfiles-updates-search-command: command used to search for .pacnew and .pasave files.
  • pacfiles-activate-no-confirm: if t, do not ask for user input when applying or discarding a merged file.
  • pacfiles-merge-file-tmp-location: location where temporary merge files are stored.


  • n and p: move forward or backwards to the next button.
  • C-c C-n and C-c C-p: move to the next and previous section headers.
  • g or r: refresh the list of files.
  • TAB: toggle hiding or showing headers

What's happening in the back

When merging a .pacnew or .pacsave update with its corresponding base file, pacfiles-mode computes a hash of the base file. The hash is used to name a temporary merge file with the format<hash>.pacmerge. If pacfiles-mode finds a .pacmerge file whose name matches the hash of a base file, the .pacmerge file is associated to the base file as its merge. When applying a merge, this temporary .pacmerge file replaces the base file and the corresponding update file is deleted.