Provided by: guestfs-tools_1.52.0-2ubuntu5_amd64 
NAME
virt-cat - Display files in a virtual machine
SYNOPSIS
virt-cat [--options] -d domname file [file ...]
virt-cat [--options] -a disk.img [-a disk.img ...] file [file ...]
Old-style:
virt-cat domname file
virt-cat disk.img file
DESCRIPTION
"virt-cat" is a command line tool to display the contents of "file" where "file" exists in the named
virtual machine (or disk image).
Multiple filenames can be given, in which case they are concatenated together. Each filename must be a
full path, starting at the root directory (starting with '/').
"virt-cat" can be used to quickly view a file. To edit a file, use "virt-edit". For more complex cases
you should look at the guestfish(1) tool (see "USING GUESTFISH" below).
EXAMPLES
Display /etc/fstab file from inside the libvirt VM called "mydomain":
virt-cat -d mydomain /etc/fstab
Find out what packages were recently installed:
virt-cat -d mydomain /var/log/yum.log | tail
Find out who is logged on inside a virtual machine:
virt-cat -d mydomain /var/run/utmp > /tmp/utmp
who /tmp/utmp
or who was logged on:
virt-cat -d mydomain /var/log/wtmp > /tmp/wtmp
last -f /tmp/wtmp
OPTIONS
--help
Display brief help.
-a file
--add file
Add file which should be a disk image from a 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).
--blocksize=512
--blocksize=4096
--blocksize
This parameter sets the sector size of the disk image. It affects all explicitly added subsequent
disks after this parameter. Using --blocksize with no argument switches the disk sector size to the
default value which is usually 512 bytes. See also "guestfs_add_drive_opts" in guestfs(3).
-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.
-d guest
--domain guest
Add all the disks from the named libvirt guest. Domain UUIDs can be used instead of names.
--echo-keys
When prompting for keys and passphrases, virt-cat 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.
--format=raw|qcow2|..
--format
The default for the -a option is to auto-detect the format of the disk image. Using this forces the
disk format for -a options which follow on the command line. Using --format with no argument
switches back to auto-detection for subsequent -a options.
For example:
virt-cat --format=raw -a disk.img file
forces raw format (no auto-detection) for disk.img.
virt-cat --format=raw -a disk.img --format -a another.img file
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).
--key SELECTOR
Specify a key for LUKS, to automatically open a LUKS device when using the inspection.
--key NAME:key:KEY_STRING
--key UUID:key:KEY_STRING
--key all:key:KEY_STRING
"NAME" is the libguestfs device name (eg. "/dev/sda1"). "UUID" is the device UUID. "all" means
try the key against any encrypted device.
Use the specified "KEY_STRING" as passphrase.
--key NAME:file:FILENAME
--key UUID:file:FILENAME
--key all:file:FILENAME
Read the passphrase from FILENAME.
--key NAME:clevis
--key UUID:clevis
--key all:clevis
Attempt passphrase-less unlocking for the device with Clevis, over the network. Please refer to
"ENCRYPTED DISKS" in guestfs(3) for more information on network-bound disk encryption (NBDE).
Note that if any such option is present on the command line, QEMU user networking will be
automatically enabled for the libguestfs appliance.
--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.
If there are multiple encrypted devices then you may need to supply multiple keys on stdin, one per
line.
-m dev[:mountpoint[:options[:fstype]]]
--mount dev[:mountpoint[:options[:fstype]]]
Mount the named partition or logical volume on the given mountpoint.
If the mountpoint is omitted, it defaults to /.
Specifying any mountpoint disables the inspection of the guest and the mount of its root and all of
its mountpoints, so make sure to mount all the mountpoints needed to work with the filenames given as
arguments.
If you don’t know what filesystems a disk image contains, you can either run guestfish without this
option, then list the partitions, filesystems and LVs available (see "list-partitions", "list-
filesystems" and "lvs" commands), or you can use the virt-filesystems(1) program.
The third (and rarely used) part of the mount parameter is the list of mount options used to mount
the underlying filesystem. If this is not given, then the mount options are either the empty string
or "ro" (the latter if the --ro flag is used). By specifying the mount options, you override this
default choice. Probably the only time you would use this is to enable ACLs and/or extended
attributes if the filesystem can support them:
-m /dev/sda1:/:acl,user_xattr
Using this flag is equivalent to using the "mount-options" command.
The fourth part of the parameter is the filesystem driver to use, such as "ext3" or "ntfs". This is
rarely needed, but can be useful if multiple drivers are valid for a filesystem (eg: "ext2" and
"ext3"), or if libguestfs misidentifies a filesystem.
-v
--verbose
Enable verbose messages for debugging.
-V
--version
Display version number and exit.
-x Enable tracing of libguestfs API calls.
OLD-STYLE COMMAND LINE ARGUMENTS
Previous versions of virt-cat allowed you to write either:
virt-cat disk.img [disk.img ...] file
or
virt-cat guestname file
whereas in this version you should use -a or -d respectively to avoid the confusing case where a disk
image might have the same name as a guest.
For compatibility the old style is still supported.
LOG FILES
To list out the log files from guests, see the related tool virt-log(1). It understands binary log
formats such as the systemd journal.
To follow (tail) text log files, use virt-tail(1).
WINDOWS PATHS
"virt-cat" has a limited ability to understand Windows drive letters and paths (eg. E:\foo\bar.txt).
If and only if the guest is running Windows then:
• Drive letter prefixes like "C:" are resolved against the Windows Registry to the correct filesystem.
• Any backslash ("\") characters in the path are replaced with forward slashes so that libguestfs can
process it.
• The path is resolved case insensitively to locate the file that should be displayed.
There are some known shortcomings:
• Some NTFS symbolic links may not be followed correctly.
• NTFS junction points that cross filesystems are not followed.
USING GUESTFISH
guestfish(1) is a more powerful, lower level tool which you can use when "virt-cat" doesn't work.
Using "virt-cat" is approximately equivalent to doing:
guestfish --ro -i -d domname download file -
where "domname" is the name of the libvirt guest, and "file" is the full path to the file. Note the
final "-" (meaning "output to stdout").
The command above uses libguestfs’s guest inspection feature and so does not work on guests that
libguestfs cannot inspect, or on things like arbitrary disk images that don't contain guests. To display
a file from a disk image directly, use:
guestfish --ro -a disk.img -m /dev/sda1 download file -
where disk.img is the disk image, /dev/sda1 is the filesystem within the disk image, and "file" is the
full path to the file.
EXIT STATUS
This program returns 0 if successful, or non-zero if there was an error.
SEE ALSO
guestfs(3), guestfish(1), virt-copy-out(1), virt-edit(1), virt-log(1), virt-tail(1), virt-tar-out(1),
http://libguestfs.org/.
AUTHOR
Richard W.M. Jones http://people.redhat.com/~rjones/
COPYRIGHT
Copyright (C) 2010-2023 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.
guestfs-tools-1.52.0 2024-04-01 virt-cat(1)