5 virt-cat - Display files in a virtual machine
9 virt-cat [--options] -d domname file [file ...]
11 virt-cat [--options] -a disk.img [-a disk.img ...] file [file ...]
17 virt-cat disk.img file
21 C<virt-cat> is a command line tool to display the contents of C<file>
22 where C<file> exists in the named virtual machine (or disk image).
24 Multiple filenames can be given, in which case they are concatenated
25 together. Each filename must be a full path, starting at the root
26 directory (starting with '/').
28 C<virt-cat> can be used to quickly view a file. To edit a file, use
29 C<virt-edit>. For more complex cases you should look at the
30 L<guestfish(1)> tool (see L</USING GUESTFISH> below).
34 Display C</etc/fstab> file from inside the libvirt VM called
37 virt-cat -d mydomain /etc/fstab
39 List syslog messages from a VM disk image file:
41 virt-cat -a disk.img /var/log/messages | tail
43 Find out what DHCP IP address a VM acquired:
45 virt-cat -d mydomain /var/log/messages | \
46 grep 'dhclient: bound to' | tail
48 Find out what packages were recently installed:
50 virt-cat -d mydomain /var/log/yum.log | tail
52 Find out who is logged on inside a virtual machine:
54 virt-cat -d mydomain /var/run/utmp > /tmp/utmp
59 virt-cat -d mydomain /var/log/wtmp > /tmp/wtmp
74 Add I<file> which should be a disk image from a virtual machine. If
75 the virtual machine has multiple block devices, you must supply all of
76 them with separate I<-a> options.
78 The format of the disk image is auto-detected. To override this and
79 force a particular format use the I<--format=..> option.
83 =item B<--connect> URI
85 If using libvirt, connect to the given I<URI>. If omitted, then we
86 connect to the default libvirt hypervisor.
88 If you specify guest block devices directly (I<-a>), then libvirt is
93 =item B<--domain> guest
95 Add all the disks from the named libvirt guest.
99 When prompting for keys and passphrases, virt-cat normally turns
100 echoing off so you cannot see what you are typing. If you are not
101 worried about Tempest attacks and there is no one else in the room you
102 can specify this flag to see what you are typing.
104 =item B<--format=raw|qcow2|..>
108 The default for the I<-a> option is to auto-detect the format of the
109 disk image. Using this forces the disk format for I<-a> options which
110 follow on the command line. Using I<--format> with no argument
111 switches back to auto-detection for subsequent I<-a> options.
115 virt-cat --format=raw -a disk.img file
117 forces raw format (no auto-detection) for C<disk.img>.
119 virt-cat --format=raw -a disk.img --format -a another.img file
121 forces raw format (no auto-detection) for C<disk.img> and reverts to
122 auto-detection for C<another.img>.
124 If you have untrusted raw-format guest disk images, you should use
125 this option to specify the disk format. This avoids a possible
126 security problem with malicious guests (CVE-2010-3851).
128 =item B<--keys-from-stdin>
130 Read key or passphrase parameters from stdin. The default is
131 to try to read passphrases from the user by opening C</dev/tty>.
137 Enable verbose messages for debugging.
143 Display version number and exit.
147 Enable tracing of libguestfs API calls.
151 =head1 OLD-STYLE COMMAND LINE ARGUMENTS
153 Previous versions of virt-cat allowed you to write either:
155 virt-cat disk.img [disk.img ...] file
159 virt-cat guestname file
161 whereas in this version you should use I<-a> or I<-d> respectively
162 to avoid the confusing case where a disk image might have the same
165 For compatibility the old style is still supported.
167 =head1 USING GUESTFISH
169 L<guestfish(1)> is a more powerful, lower level tool which you can use
170 when C<virt-cat> doesn't work.
172 Using C<virt-cat> is approximately equivalent to doing:
174 guestfish --ro -i -d domname download file -
176 where C<domname> is the name of the libvirt guest, and C<file> is the
177 full path to the file. Note the final C<-> (meaning "output to
180 The command above uses libguestfs's guest inspection feature and so
181 does not work on guests that libguestfs cannot inspect, or on things
182 like arbitrary disk images that don't contain guests. To display a
183 file from a disk image directly, use:
185 guestfish --ro -a disk.img -m /dev/sda1 download file -
187 where C<disk.img> is the disk image, C</dev/sda1> is the filesystem
188 within the disk image to edit, and C<file> is the full path to the
193 Libvirt guest names can contain arbitrary characters, some of which
194 have meaning to the shell such as C<#> and space. You may need to
195 quote or escape these characters on the command line. See the shell
196 manual page L<sh(1)> for details.
205 L<http://libguestfs.org/>.
209 Richard W.M. Jones L<http://people.redhat.com/~rjones/>
213 Copyright (C) 2010-2011 Red Hat Inc.
215 This program is free software; you can redistribute it and/or modify
216 it under the terms of the GNU General Public License as published by
217 the Free Software Foundation; either version 2 of the License, or
218 (at your option) any later version.
220 This program is distributed in the hope that it will be useful,
221 but WITHOUT ANY WARRANTY; without even the implied warranty of
222 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
223 GNU General Public License for more details.
225 You should have received a copy of the GNU General Public License
226 along with this program; if not, write to the Free Software
227 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.