SYSCONFTOOL(1)							    sysconftool 						    SYSCONFTOOL(1)

NAME

       sysconftool - install configuration files

SYNOPSIS

       sysconftool [options] [filename.dist...]

DESCRIPTION

       sysconftool is a development utility that helps to install application configuration files.  sysconftool allows an existing application to
       be upgraded without losing the older version's configuration settings.

       A new version of an application often introduces new configuration settings. Sometimes obsolete configuration settings are removed.
       Existing configuration settings may also now have additional options, or certain options are no longer valid any more. Because of this, an
       application upgrade usually installs a fresh set of configuration files, containing a default configuration that's known to work. Keeping
       the existing files carries the risk of the application failing to function properly due to a configuration that is no longer valid.

       A typical application installation script copies over configuration files with default settings. Existing configuration files are backed up
       or overwritten. With sysconftool, an application will install a configuration file names filename.dist, instead of filename. Then, the
       application's installation script runs sysconftool.  sysconftool copies filename.dist to filename, but also checks if filename from an
       older version of the application already exist. If filename an older sysconftool-installed configuration file, it's configuration settings
       replace the defaults in filename.dist, which is then subsequently installed as filename.  sysconftool is smart enough to:

       o   Remove configuration settings that no longer exist.

       o   Add new configuration settings.

       o   Do not preserve an older configuration setting if there's a possibility that it is no longer valid in the new version of the
	   application.

       sysconftool produces a short report when it runs. The report lists every configuration setting in $filename.dist, and its disposition. The
       possible dispositions are:

       new
	   This a new configuration setting that wasn't found in the existing $filename.

       unchanged
	   This setting's value was taken from the existing $filename, replacing the default value provided by $filename.dist.

       UPDATED
	   This setting has been previously set in $filename, but the setting's value may no longer be valid in the new version of the
	   application, so its default value is taken from $filename.dist, and it may need to be manually adjusted.

       All this logic is based on some additional metadata that must be included in each configuration file, that sysconftool reads. For this to
       work, both the old and the new version of the application must be sysconftool-ized.  sysconftool operates in a fail-safe mode. If the old
       version did not use sysconftool, $filename is backed up to $filename.bak, and $filename is copied to $filename. This is what would
       essentially happen anyway without sysconftool. The local configuration needs to be reentered into $filename, so nothing is lost. However,
       the next upgrade will see sysconftool do its job.

ADDING SYSCONFTOOL SUPPORT TO AN EXISTING APPLICATION

       sysconftool requires the application to use autoconf and automake. The first step is to run the sysconftoolize script from the
       application's source directory.	sysconftoolize copies the sysconftool script to the current directory, and appends a default
       install-configure rule to Makefile.am. After running sysconftoolize the macro AC_PROG_SYSCONFTOOL must be manually added to configure.in,
       and Makefile.am must be modified as follows.

       Makefile.am must be modified to install configuration files as filename.dist instead of filename. The default install-configure rule
       assumes that sysconf_DATA lists all configuration files in sysconfdir, and runs sysconftool on them. This will usually have to be modified,
       according to the application's individual needs. Finally, Makefile.am must be modified to distribute the sysconftool script in the
       application's source distribution. Adding sysconftool to EXTRA_DIST is what's needed in most cases.

       Finally, certain sysconftool magic incantations must be added to the application's configuration files, see sysconftool(7)[1] for more
       information. The last step involves updating the application's INSTALL instructions, so that the application can be properly installed. The
       following instructions must be added to INSTALL:

	1. Run "make install-configure" after "make install".

	2. If this is the first sysconftool-ized version, DO NOT simply copy over the old configuration files, and overwrite the new configuration
	   files. Instead, manually edit each configuration file, and manually reset each configuration setting. This is because the new
	   configuration files include the magic code for sysconftool, which would be lost when the configuration file is overwritten.

	3. If this is not the first sysconftool-ized version, the output of make install-configure must be reviewed in order to manually adjust or
	   tweak what sysconftool did. Many large configuration files can result in lots of output, so the output of make install-configure should
	   be saved into a file, and reviewed.

SEE ALSO

       sysconftoolcheck(1)[2], sysconftool(7)[1].

AUTHORS

       Double Precision, Inc.

NOTES

	1. sysconftool(7)
	   [set $man.base.url.for.relative.links]/sysconftool.7.html

	2. sysconftoolcheck(1)
	   [set $man.base.url.for.relative.links]/sysconftoolcheck.1.html

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