--- name: "dpkg-fsys-usrunmess" section: "8" platform: "linux" package: "dpkg" version: "1.21.23" release: "Debian 12 (Bookworm)" platforms: ["linux"] url: "https://new.carta.tech/dpkg-fsys-usrunmess" --- # dpkg-fsys-usrunmess(8) undoes the merged-/usr-via-aliased-dirs mess ## NAME dpkg-fsys-usrunmess - undoes the merged-/usr-via-aliased-dirs mess ## SYNOPSIS **dpkg-fsys-usrunmess** \[**option**...\] ## DESCRIPTION **dpkg-fsys-usrunmess** is a tool to fix up filesystems that have been installed anew with recent installers with unfortunate defaults or migrated to the broken merged /usr via aliased directories layout, which is **not** supported by dpkg. See the dpkg FAQ. **Note**: In Debian its tech-ctte has decreed that on the release after bookworm the non-usrmerged layout is not going to be supported, and thus some of its maintainers might not fix issues or intentionally remove non-usrmerged support, so you will need decide and pick your poison. The program will perform the following overall actions: - • Check whether the system needs to be switched, otherwise do nothing, - • Check for dpkg database consistency and otherwise abort. - • Generate and install a regression prevention package, if requested on the command-line or otherwise on the prompt. - • Get the list of files and alternatives that need to be restored. - • Look for untracked kernel modules files that need to be moved too. - • Create a shadow hierarchy under */.usrunmess*, by creating the directories symlinks or hardlinking or copying the files as needed. - • Prompt for confirmation before proceeding, if requested on the command-line. - • Lock the dpkg database. - • Mark all packages as half-configured to force running maintainer scripts that might need to recreate files. - • Replace the aliased directories with the shadow ones, by creating a backup of the old symlinked directories and renaming the shadow ones over. - • Relabel MAC information for directories and symlinks if necessary. - • Remove backup symlinks. - • Remove old moved objects, but defer directory removal. - • Remove old deferred directories that are not referenced by dpkg-query. - • Remove shadow root directory. - • Register a **policy-rc.d** to disallow service actions, which means that services might need to be restarted afterwards, ideally via a reboot. - • Reconfigure all packages. - • Unregister the **policy-rc.d** and restore the alternatives state. **Note**: When running the program from some shells such as [**bash**(1)](/bash/1.md) or [**zsh**(1)](/zsh/1.md), after executing it, you might need to request the shell to forget all remembered executable locations with for example `"hash -r"`. **Note**: Some directories might linger after the migration in case they contain untracked files. A list is printed once the script has finished for further investigation. **Warning**: Note that this operation has the potential to render the system unusable or broken in case of a sudden crash or reboot, unexpected state of the system, or possible bugs in the script. Be prepared with recovery media and consider doing backups beforehand. ## OPTIONS - **-p**, **--prompt** Prompt at the time of no return, so that the debug output or the shadow hierarchy can be evaluated before proceeding. - **--prevention** - **--no-prevention** Enables or disables generating and installing a regression prevention package into the system. If no option has been specified, the action to take will be prompted. The generated package contains the **Protected** field set to **yes** to protect against accidental removal of the package. - **-n**, **--no-act** - **--dry-run** This option enables the dry-run mode, where no destructive action takes place, only the preparatory part. - **-?**, **--help** Show the usage message and exit. - **--version** Show the version and exit. ## ENVIRONMENT - **DPKG\_USRUNMESS\_NOACT** This setting defines whether to enable dry-run mode. ## SEE ALSO \.