1SYSCONFTOOL(1) sysconftool SYSCONFTOOL(1)
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6 sysconftool - install configuration files
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9 sysconftool [options] [filename.dist...]
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12 sysconftool is a development utility that helps to install application
13 configuration files. sysconftool allows an existing application to be
14 upgraded without losing the older version's configuration settings.
15 A new version of an application often introduces new configuration
17 settings. Sometimes obsolete configuration settings are removed.
18 Existing configuration settings may also now have additional options,
19 or certain options are no longer valid any more. Because of this, an
20 application upgrade usually installs a fresh set of configuration
21 files, containing a default configuration that's known to work. Keeping
22 the existing files carries the risk of the application failing to
23 function properly due to a configuration that is no longer valid.
24 A typical application installation script copies over configuration
26 files with default settings. Existing configuration files are backed up
27 or overwritten. With sysconftool, an application will install a
28 configuration file names filename.dist, instead of filename. Then, the
29 application's installation script runs sysconftool. sysconftool copies
30 filename.dist to filename, but also checks if filename from an older
31 version of the application already exist. If filename an older
32 sysconftool-installed configuration file, it's configuration settings
33 replace the defaults in filename.dist, which is then subsequently
34 installed as filename. sysconftool is smart enough to:
35 • Remove configuration settings that no longer exist.
37 • Add new configuration settings.
39 • Do not preserve an older configuration setting if there's a
41 possibility that it is no longer valid in the new version of the
42 application.
43 sysconftool produces a short report when it runs. The report lists
45 every configuration setting in $filename.dist, and its disposition. The
46 possible dispositions are:
47 new
49 This a new configuration setting that wasn't found in the existing
50 $filename.
51 unchanged
53 This setting's value was taken from the existing $filename,
54 replacing the default value provided by $filename.dist.
55 UPDATED
57 This setting has been previously set in $filename, but the
58 setting's value may no longer be valid in the new version of the
59 application, so its default value is taken from $filename.dist, and
60 it may need to be manually adjusted.
61 All this logic is based on some additional metadata that must be
63 included in each configuration file, that sysconftool reads. For this
64 to work, both the old and the new version of the application must be
65 sysconftool-ized. sysconftool operates in a fail-safe mode. If the old
66 version did not use sysconftool, $filename is backed up to
67 $filename.bak, and $filename is copied to $filename. This is what would
68 essentially happen anyway without sysconftool. The local configuration
69 needs to be reentered into $filename, so nothing is lost. However, the
70 next upgrade will see sysconftool do its job.
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73 sysconftool requires the application to use autoconf and automake. The
74 first step is to run the sysconftoolize script from the application's
75 source directory. sysconftoolize creates a symbolic link to the
76 sysconftool script from the current directory, and appends a default
77 install-configure rule to Makefile.am. sysconftoolize with the --copy
78 option copies the script, instead of creating a symbolic link.
79 After running sysconftoolize the macro AC_PROG_SYSCONFTOOL must be
81 manually added to configure.in, and Makefile.am must be modified as
82 follows.
83 Makefile.am must be modified to install configuration files as
85 filename.dist instead of filename. The default install-configure rule
86 assumes that sysconf_DATA lists all configuration files in sysconfdir,
87 and runs sysconftool on them. This will usually have to be modified,
88 according to the application's individual needs. Finally, Makefile.am
89 must be modified to distribute the sysconftool script in the
90 application's source distribution. Adding sysconftool to EXTRA_DIST is
91 what's needed in most cases.
92 Finally, certain sysconftool magic incantations must be added to the
94 application's configuration files, see sysconftool(7)[1] for more
95 information. The last step involves updating the application's INSTALL
96 instructions, so that the application can be properly installed. The
97 following instructions must be added to INSTALL:
98 1. Run "make install-configure" after "make install".
100 2. If this is the first sysconftool-ized version, DO NOT simply copy
102 over the old configuration files, and overwrite the new
103 configuration files. Instead, manually edit each configuration
104 file, and manually reset each configuration setting. This is
105 because the new configuration files include the magic code for
106 sysconftool, which would be lost when the configuration file is
107 overwritten.
108 3. If this is not the first sysconftool-ized version, the output of
110 make install-configure must be reviewed in order to manually adjust
111 or tweak what sysconftool did. Many large configuration files can
112 result in lots of output, so the output of make install-configure
113 should be saved into a file, and reviewed.
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116 sysconftoolcheck(1)[2], sysconftool(7)[1].
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119 Double Precision, Inc.
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122 1. sysconftool(7)
123 [set $man.base.url.for.relative.links]/sysconftool.7.html
124 2. sysconftoolcheck(1)
126 [set $man.base.url.for.relative.links]/sysconftoolcheck.1.html
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