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NAME

       virt-diff - Differences between files in two virtual machines

SYNOPSIS

        virt-diff [--options] -d domain1 -D domain2

        virt-diff [--options] -a disk1.img [-a ...] -A disk2.img [-A ...]

DESCRIPTION

       "virt-diff" lists the differences between files in two virtual machines
       or disk images.  The usual use case is to show the changes in a VM
       after it has been running for a while, by taking a snapshot, running
       the VM, and then using this tool to show what changed between the new
       VM state and the old snapshot.

       This tool will find differences in filenames, file sizes, checksums,
       extended attributes, file content and more from a virtual machine or
       disk image.  However it does not look at the boot loader, unused space
       between partitions or within filesystems, "hidden" sectors and so on.
       In other words, it is not a security or forensics tool.

       To specify two guests, you have to use the -a or -d option(s) for the
       first guest, and the -A or -D option(s) for the second guest.  The
       common case is:

        virt-diff -a old.img -A new.img

       or using names known to libvirt:

        virt-diff -d oldguest -D newguest

OPTIONS

       --help
           Display brief help.

       -a file
       --add file
           Add file which should be a disk image from the first virtual
           machine.  If the virtual machine has multiple block devices, you
           must supply all of them with separate -a options.

           The format of the disk image is auto-detected.  To override this
           and force a particular format use the --format=.. option.

       -a URI
       --add URI
           Add a remote disk.  See "ADDING REMOTE STORAGE" in guestfish(1).

       --all
           Same as --extra-stats --times --uids --xattrs.

       --atime
           The default is to ignore changes in file access times, since those
           are unlikely to be interesting.  Using this flag shows atime
           differences as well.

       -A file
       -A URI
           Add a disk image from the second virtual machine.

       --checksum
       --checksum=crc|md5|sha1|sha224|sha256|sha384|sha512
           Use a checksum over file contents to detect when regular files have
           changed content.

           With no argument, this defaults to using md5.  Using an argument,
           you can select the checksum type to use.  If the flag is omitted
           then file times and size are used to determine if a file has
           changed.

       -c URI
       --connect URI
           If using libvirt, connect to the given URI.  If omitted, then we
           connect to the default libvirt hypervisor.

           If you specify guest block devices directly (-a), then libvirt is
           not used at all.

       --csv
           Write out the results in CSV format (comma-separated values).  This
           format can be imported easily into databases and spreadsheets, but
           read "NOTE ABOUT CSV FORMAT" below.

       --dir-links
           The default is to ignore changed in the number of links in
           directory entries, since those are unlikely to be interesting.
           Using this flag shows changes to the nlink field of directories.

       --dir-times
           The default is to ignore changed times on directory entries, since
           those are unlikely to be interesting.  Using this flag shows
           changes to the time fields of directories.

       -d guest
       --domain guest
           Add all the disks from the named libvirt guest, as the first guest.
           Domain UUIDs can be used instead of names.

       -D guest
           Add all the disks from the named libvirt guest, as the second
           guest.  Domain UUIDs can be used instead of names.

       --echo-keys
           When prompting for keys and passphrases, virt-diff normally turns
           echoing off so you cannot see what you are typing.  If you are not
           worried about Tempest attacks and there is no one else in the room
           you can specify this flag to see what you are typing.

       --extra-stats
           Display extra stats.

       --format=raw|qcow2|..
       --format
           The default for the -a/-A option is to auto-detect the format of
           the disk image.  Using this forces the disk format for -a/-A
           options which follow on the command line.  Using --format with no
           argument switches back to auto-detection for subsequent -a/-A
           options.

           For example:

            virt-diff --format=raw -a disk.img [...]

           forces raw format (no auto-detection) for "disk.img".

            virt-diff --format=raw -a disk.img --format -a another.img [...]

           forces raw format (no auto-detection) for "disk.img" and reverts to
           auto-detection for "another.img".

           If you have untrusted raw-format guest disk images, you should use
           this option to specify the disk format.  This avoids a possible
           security problem with malicious guests (CVE-2010-3851).

       -h
       --human-readable
           Display file sizes in human-readable format.

           This option only has effect in -lR output mode.  See "RECURSIVE
           LONG LISTING" above.

       --keys-from-stdin
           Read key or passphrase parameters from stdin.  The default is to
           try to read passphrases from the user by opening "/dev/tty".

       --times
           Display time fields.

       --time-days
           Display time fields as days before now (negative if in the future).

           Note that 0 in output means "up to 1 day before now", or that the
           age of the file is between 0 and 86399 seconds.

       --time-relative
           Display time fields as seconds before now (negative if in the
           future).

       --time-t
           Display time fields as seconds since the Unix epoch.

       --uids
           Display UID and GID fields.

       -v
       --verbose
           Enable verbose messages for debugging.

       -V
       --version
           Display version number and exit.

       -x  Enable tracing of libguestfs API calls.

       --xattrs
           Display extended attributes.

NOTE ABOUT CSV FORMAT

       Comma-separated values (CSV) is a deceptive format.  It seems like it
       should be easy to parse, but it is definitely not easy to parse.

       Myth: Just split fields at commas.  Reality: This does not work
       reliably.  This example has two columns:

        "foo,bar",baz

       Myth: Read the file one line at a time.  Reality: This does not work
       reliably.  This example has one row:

        "foo
        bar",baz

       For shell scripts, use "csvtool" (http://merjis.com/developers/csv also
       packaged in major Linux distributions).

       For other languages, use a CSV processing library (eg. "Text::CSV" for
       Perl or Python's built-in csv library).

       Most spreadsheets and databases can import CSV directly.

EXIT STATUS

       This program returns 0 if successful, or non-zero if there was an
       error.

SEE ALSO

       guestfs(3), guestfish(1), virt-cat(1), virt-copy-out(1), virt-ls(1),
       virt-tar-out(1), http://libguestfs.org/.

AUTHOR

       Richard W.M. Jones http://people.redhat.com/~rjones/

COPYRIGHT

       Copyright (C) 2009-2014 Red Hat Inc.

LICENSE

       This program is free software; you can redistribute it and/or modify it
       under the terms of the GNU General Public License as published by the
       Free Software Foundation; either version 2 of the License, or (at your
       option) any later version.

       This program is distributed in the hope that it will be useful, but
       WITHOUT ANY WARRANTY; without even the implied warranty of
       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
       General Public License for more details.

       You should have received a copy of the GNU General Public License along
       with this program; if not, write to the Free Software Foundation, Inc.,
       51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

BUGS

       To get a list of bugs against libguestfs, use this link:
       https://bugzilla.redhat.com/buglist.cgi?component=libguestfs&product=Virtualization+Tools

       To report a new bug against libguestfs, use this link:
       https://bugzilla.redhat.com/enter_bug.cgi?component=libguestfs&product=Virtualization+Tools

       When reporting a bug, please supply:

       ·   The version of libguestfs.

       ·   Where you got libguestfs (eg. which Linux distro, compiled from
           source, etc)

       ·   Describe the bug accurately and give a way to reproduce it.

       ·   Run libguestfs-test-tool(1) and paste the complete, unedited output
           into the bug report.



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