MERGEMASTER(8) BSD System Manager's Manual MERGEMASTER(8)NAMEmergemaster — merge configuration files, et al during an upgrade
SYNOPSISmergemaster [-scrvhpCP] [-a|iFU] [-m /path/to/sources]
[-t /path/to/temp/root] [-d] [-u N] [-w N]
[-A Target architecture] [-D /destdir/path]
DESCRIPTION
The mergemaster utility is a Bourne shell script which is designed to aid
you in updating the various configuration and other files associated with
FreeBSD. It is HIGHLY recommended that you back up your /etc directory
before beginning this process.
The script uses /usr/src/Makefile to build a temporary root environment
from / down, populating that environment with the various files. You can
specify a different source directory with the -m command line option, or
specify the destination directory with the -D option. It then compares
each file in that environment to its installed counterpart. When the
script finds a change in the new file, or there is no installed version
of the new file it gives you four options to deal with it. You can
install the new file as is, delete the new file, merge the old and new
files (as appropriate) using sdiff(1) or leave the file in the temporary
root environment to merge by hand later.
By default it creates the temporary root in /var/tmp/temproot and com‐
pares the Version Control System (VCS) Id strings ($FreeBSD) for files
that have them, deleting the temporary file if the strings match. If
there is no Id string, or if the strings are different it compares the
files themselves. You can also specify that the script ignore the Id
strings and compare every file with the -s option. Using the -F option
mergemaster will install the new file for you if they differ only by VCS
strings.
The merge menu option is designed to let you easily combine your cus‐
tomizations from the old version of a file into the new one. While you
can use the merge function to incorporate changes from files that you
have not customized, it is not recommended.
The mergemaster utility checks your umask and issues a warning for any‐
thing other than 022. While it is not mandatory to grant world read per‐
missions for most configuration files, you may run into problems without
them. If you choose a umask other than 022 and experience trouble later
this could be the cause. /etc/master.passwd is treated as a special
case. If you choose to install this file or a merged version of it the
file permissions are always 600 (rw-------) for security reasons. After
installing an updated version of this file you should probably run
pwd_mkdb(8) with the -p option to rebuild your password databases and
recreate /etc/passwd.
The script uses the owner and group ids that the files are created with
by /usr/src/etc/Makefile, and file permissions as specified by the umask.
Unified diffs are used by default to display any differences unless you
choose context diffs.
The mergemaster utility will source scripts that you specify right before
it starts the comparison, and after it is done running. The easiest way
to handle this is to place the path to the script(s) in the appropriate
variables in your .mergemasterrc file. The script sourced before compar‐
ison is named in MM_PRE_COMPARE_SCRIPT, and the one sourced after the
script is done is MM_EXIT_SCRIPT. This is the recommended way to specify
local modifications, or files that you want to give special handling to.
This includes files that you want to be deleted without being compared.
Because the named scripts are sourced from within mergemaster, all of the
script's variables are available for use in your custom script. You can
also use /etc/mergemaster.rc which will be read before .mergemasterrc.
Options specified on the command line are updated last, and therefore can
override both files.
When the comparison is done if there are any files remaining in the temp‐
root directory they will be listed, and if the -a option is not in use
the user will be given the option of deleting the temproot directory. If
there are no files remaining in the temproot directory it will be
deleted.
The options are as follows:
-s Perform a strict comparison, diffing every pair of files.
This comparison is performed line by line, without regard to
VCS Ids.
-c Use context diffs instead of unified diffs.
-r Re-run mergemaster on a previously cleaned directory, skip‐
ping the creation of the temporary root environment. This
option is compatible with all other options.
-v Be more verbose about the process. You should probably use
this option the first time you run mergemaster. This option
also gives you a list of files that exist only in the
installed version of /etc.
-a Run automatically. This option will leave all the files that
differ from the installed versions in the temporary directory
to be dealt with by hand. If the temproot directory exists,
it creates a new one in a previously non-existent directory.
This option unsets the verbose flag, and is not compatible
with -i, -F, or -U. Setting -a makes -w superfluous.
-h Display usage and help information.
-i Automatically install any files that do not exist in the des‐
tination directory.
-p Pre-buildworld mode. Compares only files known to be essen‐
tial to the success of {build|install}world, including
/etc/make.conf.
-F If the files differ only by VCS Id ($FreeBSD) install the new
file.
-C After a standard mergemaster run, compares your
rc.conf[.local] options to the defaults.
-P Preserve files that you replace in
/var/tmp/mergemaster/preserved-files-<date>, or another
directory you specify in your mergemaster rc file.
-U Attempt to auto upgrade files that have not been user modi‐
fied.
-m /path/to/sources
Specify the path to the directory where you want to do the
make(1). (In other words, where your sources are, but -s was
already taken.) In previous versions of mergemaster you
needed to specify the path all the way to src/etc. Starting
with r186678 you only need to specify the path to src.
mergemaster will convert the path for you if you use the old
method.
-t /path/to/temp/root
Create the temporary root environment in /path/to/temp/root
instead of the default /var/tmp/temproot.
-d Add the date and time to the name of the temporary root
directory. If -t is specified, this option must follow it if
you want the date added too.
-u N Specify a numeric umask. The default is 022.
-w N Supply an alternate screen width to the sdiff(1) command in
numbers of columns. The default is 80.
-A Target architecture
Specify an alternative TARGET_ARCH architecture name.
-D /path Specify the destination directory for the installed files.
ENVIRONMENT
The mergemaster utility uses the PAGER environment variable if set. Oth‐
erwise it uses more(1). If PAGER specifies a program outside its limited
PATH without specifying the full path, mergemaster prompts you with
options on how to proceed. The MM_PRE_COMPARE_SCRIPT and MM_EXIT_SCRIPT
variables are used as described above. Other variables that are used by
the script internally can be specified in .mergemasterrc as described in
more detail below.
FILES
/etc/mergemaster.rc
$HOME/.mergemasterrc
The mergemaster utility will . (source) these files if they exist. Com‐
mand line options will override rc file options. $HOME/.mergemasterrc
overrides /etc/mergemaster.rc. Here is an example with all values com‐
mented out:
# These are options for mergemaster, with their default values listed
# The following options have command line overrides
#
# The target architecture (-A, unset by default)
#ARCHSTRING='TARGET_ARCH=<foo>'
#
# Sourcedir is the directory to do the 'make' in (-m)
#SOURCEDIR='/usr/src'
#
# Directory to install the temporary root environment into (-t)
#TEMPROOT='/var/tmp/temproot'
#
# Specify the destination directory for the installed files (-D)
#DESTDIR=
#
# Strict comparison skips the VCS Id test and compares every file (-s)
#STRICT=no
#
# Type of diff, such as unified, context, etc. (-c)
#DIFF_FLAG='-u'
#
# Install the new file if it differs only by VCS Id ($FreeBSD, -F)
#FREEBSD_ID=
#
# Verbose mode includes more details and additional checks (-v)
#VERBOSE=
#
# Automatically install files that do not exist on the system already (-i)
#AUTO_INSTALL=
#
# Automatically upgrade files that have not been user modified (-U)
#AUTO_UPGRADE=
#
# Compare /etc/rc.conf[.local] to /etc/defaults/rc.conf (-C)
#COMP_CONFS=
#
# Preserve files that you replace (-P)
#PRESERVE_FILES=
#PRESERVE_FILES_DIR=/var/tmp/mergemaster/preserved-files-`date +%y%m%d-%H%M%S`
#
# The umask for mergemaster to compare the default file's modes to (-u)
#NEW_UMASK=022
#
# The following options have no command line overrides
#
# Files to always avoid comparing
#IGNORE_FILES='/etc/motd /etc/printcap foo bar'
#
# Additional options for diff. This will get unset when using -s.
#DIFF_OPTIONS='-Bb' # Ignore changes in whitespace
#
# Location to store the list of mtree values for AUTO_UPGRADE purposes
#MTREEDB='/var/db'
#
# For those who just cannot stand including the full path to PAGER
#DONT_CHECK_PAGER=
#
# If you set 'yes' above, make sure to include the PATH to your pager
#PATH=/bin:/usr/bin:/usr/sbin
#
# Delete stale files in /etc/rc.d without prompting
#DELETE_STALE_RC_FILES=
#
# Specify the path to scripts to run before the comparison starts,
# and/or after the script has finished its work
#MM_PRE_COMPARE_SCRIPT=
#MM_EXIT_SCRIPT=
EXIT STATUS
Exit status is 0 on successful completion, or if the user bails out manu‐
ally at some point during execution.
Exit status is 1 if it fails for one of the following reasons:
Invalid command line option
Failure to create the temporary root environment
Failure to populate the temporary root
Presence of the 'nodev' option in <DESTDIR>/etc/fstab
Failure to install a file
EXAMPLES
Typically all you will need to do is type mergemaster at the prompt and
the script will do all the work for you.
To use context diffs and have mergemaster explain more things as it goes
along, use:
# mergemaster-cv
To specify that mergemaster put the temporary root environment in
/usr/tmp/root, use:
# mergemaster-t /usr/tmp/root
To specify a 110 column screen with a strict comparison, use:
# mergemaster-sw 110
SEE ALSOdiff(1), make(1), more(1), sdiff(1), pwd_mkdb(8)
/usr/src/etc/Makefile
Nik Clayton, The Cutting Edge (using make world),
http://www.FreeBSD.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html.
HISTORY
The mergemaster utility was first publicly available on one of my web
pages in a much simpler form under the name comproot on 13 March 1998.
The idea for creating the temporary root environment comes from Nik Clay‐
ton's make world tutorial which is referenced above.
AUTHORS
This manual page and the script itself were written by Douglas Barton
⟨DougB@FreeBSD.org⟩.
BUGS
There are no known bugs. Please report any problems, comments or sugges‐
tions to the author. Several of the improvements to this program have
come from user suggestions. Thank you.
BSD March 13, 2010 BSD
