cme - Man Page

Check or edit configuration data with Config::Model


version 1.040


  # general synopsis
  cme [ global_options ] command application [ options ] [ file ] [ modification_instructions ]

  # edit dpkg config with GUI (and Config::Model::Dpkg)
  cme edit dpkg

  # read data from arbitrary file (for model read from alternate file)
  cme check dpkg-copyright -file path/to/file

  # edit /etc/sshd_config (with Config::Model::OpenSsh)
  sudo cme edit sshd

  # edit ~/.ssh/config (with Config::Model::OpenSsh)
  cme edit ssh

  # just check the validity of a file. Both commands are equivalent
  cme check multistrap file.conf
  cme check multistrap -file file.conf

  # check dpkg files, update deprecated parameters and save
  cme migrate dpkg

  # like migrate, but also apply all suggested fixes
  cme fix dpkg

  # modify configuration with command line
  cme modify dpkg source 'format="(3.0) quilt"'

  # likewise with an application that accepts file override
  cme modify dpkg-copyright 'Comment="Modified with cme"'

  # edit a file (file name specification is mandatory here)
  cme edit multistrap my.conf

  # map conf data to a fuse file system
  cme fusefs multistrap my.conf -d fuse_dir

  # likewise for dpkg data
  cme fusefs dpkg -d fuse_dir

  # list all available applications (depends on your installation)
  cme list


Depending on the command described below, cme program will use Config::Model configuration descriptions to check or modify or fix configuration files.

The 3rd parameter specify the application you want to work on. Most of the time, the relevant configuration file(s) will be found by cme. This is the most simple case. For instance:

  sudo cme check popcon

Some application like multistrap have no constraint on the configuration file name and will require you to specify your configuration file name:

  cme check multistrap raspbian.conf


  cme check multistrap -file raspbian.conf

Configuration file specification

The configuration of an application can take different forms. Either several files (like debian packages), a single file with a predefined file (popcon), or a single file with an arbitrary file name (multistrap).

When needed the configuration file name is specified as the 3rd command argument, i.e. cme command application file_name. This applies if the application requires a configuration file name (like multistrap), or if the application allows configuration file override.

Main commands

This section describes the main commands shipped with cme. Other Config::Model extensions can bring more command. Run cme help to get the list of available commands on your system.


Show a list all applications where a model is available. This list depends on installed Config::Model modules.


Edit a configuration. By default, a Tk GUI will be opened If Config::Model::TkUI is installed. See App::Cme::Command::edit.


Edit the configuration with a shell like interface. See App::Cme::Command::shell.


Checks the content of the configuration file of an application. See App::Cme::Command::check.


Update deprecated parameters (old value are saved to new parameters) and save the new configuration. See App::Cme::Command::migrate.


Migrate data and fix warnings.  See App::Cme::Command::fix.


Modify a configuration file with the values passed on the command line.  See App::Cme::Command::modify.


Update the content of the configuration file from external data. Currently, only dpkg-copyright model support update sub command. See App::Cme::Command::update.


Map the configuration file content to a FUSE virtual file system on a directory specified with option -fuse-dir. Modifications done in the fuse file system are saved to the configuration file when the fusermount -u is run.

Global options

The following options are available for all commands:


Perform the operation even if the configuration file is missing. This may be used to create a minimal configuration file. This option is disabled by default as a missing configuration file often indicates an error during the installation of the application.


For model that support it, specify an alternate file to read and write the configuration.

You can use this option for model that require the target file to be specified (e.g. multitrap model), but file can in this case be also specified with the 4th command argument. E.g. these 2 commands have the same effect:

  cme check multistrap foo.conf
  cme check multistrap -file foo.conf

Load file even if error are found in data. Bad data are discarded


Write config data back using model order. By default, write items back using the order found in the configuration file. This feature is experimental and not supported by all backends.


Create a backup of configuration files before saving. By default, old will be appended to the backup file. I.e. foo.conf will be backed up as foo.conf.old. You can specify an alternate suffix. For instance -backup dpkg-old.


Force a save even if no change was done. Useful to reformat the configuration file.


When set, cme will exit 1 if warnings are found during check (of left after fix)


Show more information about what's going on.


Suppress all output except error messages.

Advanced options


Specify an alternate directory to find model files. Mostly useful for tests.


Specify a pseudo root directory to read and write the configuration files. (Actual default directory and file names depends on the model (See -model option). For instance, if you specify ~/mytest, the /etc/ssh/sshd_config files will be written in ~/mytest/etc/ssh/ directory.


Provides a full stack trace when exiting on error.


When set, try to load a model using directly the application name specified as 3rd parameter on the command line. Experimental.

Embedding cme

You can use cme from another program by using -ui simple option. This way you will be able to send command on the standard input of cme and get the results from the standard output.


All Config::Model logging is now based on Log::Log4perl. Logging can be configured in the following files:

A sample of a .log4config-model is provided in contrib directory in Config::Model distribution of on github <>

Without these files, the following Log4perl config is used:

 log4perl.rootLogger=WARN, Screen
 log4perl.logger.Model.Legacy = INFO, SimpleScreen
 log4perl.additivity.Model.Legacy = 0

 log4perl.appender.Screen        = Log::Log4perl::Appender::Screen
 log4perl.appender.Screen.stderr = 0
 log4perl.appender.Screen.layout = Log::Log4perl::Layout::PatternLayout
 log4perl.appender.Screen.layout.ConversionPattern = %M %m (line %L)%n

 log4perl.appender.SimpleScreen        = Log::Log4perl::Appender::Screen
 log4perl.appender.SimpleScreen.stderr = 0
 log4perl.appender.SimpleScreen.layout = Log::Log4perl::Layout::PatternLayout
 log4perl.appender.SimpleScreen.layout.ConversionPattern = %p: %m%n

 log4perl.oneMessagePerAppender = 1

Log4perl uses the following categories:


Trace change notification through configuration tree and instance.


























More categories will come.

Exit Code

cme exits 0 when no errors are found. Exit 1 otherwise.


Files may be re-ordered

cme imposes a specific ordering of the parameters of a configuration file. This ordering is derived from the documentation of the configuration, like ssh_confg. cme writes back files using this ordering.

Thus, the diff between the original configuration files and the new version of the file may be more important than expected when cme is used the first time.

Comments may be dropped

Comments are not supported in some applidations (like the one that use YAML in configuration files). Comments are dropped when using cme to edit or modify such files. For more details, see Available backend <> page.

Configuration models can lag behind the target application

If a configuration model is not up-to-date, you will get errors complaining about unknown parameters. In such a case, please file a bug on github <> or fix the model and send a pull request. You can see this example from OpenSsh <> to learn how to fix a model.

For More Information

For more information, please check:


In alphabetical order:

 Ross Vandegrift


Feedback from users are highly desired. If you find this module useful, please share your use cases, success stories with the author.

See Also

Config::Model::Model, Config::Model::Instance, Config::Model::Node, Config::Model::HashId, Config::Model::ListId, Config::Model::WarpedNode, Config::Model::Value


Dominique Dumont


2024-01-24 perl v5.38.2 User Contributed Perl Documentation