1virt-cat(1) Virtualization Support virt-cat(1)
2
6 virt-cat - Display files in a virtual machine
7
9 virt-cat [--options] -d domname file [file ...]
10 virt-cat [--options] -a disk.img [-a disk.img ...] file [file ...]
12 Old-style:
14 virt-cat domname file
16 virt-cat disk.img file
18
20 "virt-cat" is a command line tool to display the contents of "file"
21 where "file" exists in the named virtual machine (or disk image).
22 Multiple filenames can be given, in which case they are concatenated
24 together. Each filename must be a full path, starting at the root
25 directory (starting with '/').
26 "virt-cat" can be used to quickly view a file. To edit a file, use
28 "virt-edit". For more complex cases you should look at the
29 guestfish(1) tool (see "USING GUESTFISH" below).
30
32 Display /etc/fstab file from inside the libvirt VM called "mydomain":
33 virt-cat -d mydomain /etc/fstab
35 Find out what packages were recently installed:
37 virt-cat -d mydomain /var/log/yum.log | tail
39 Find out who is logged on inside a virtual machine:
41 virt-cat -d mydomain /var/run/utmp > /tmp/utmp
43 who /tmp/utmp
44 or who was logged on:
46 virt-cat -d mydomain /var/log/wtmp > /tmp/wtmp
48 last -f /tmp/wtmp
49
51 --help
52 Display brief help.
53 -a file
55 --add file
56 Add file which should be a disk image from a virtual machine. If
57 the virtual machine has multiple block devices, you must supply all
58 of them with separate -a options.
59 The format of the disk image is auto-detected. To override this
61 and force a particular format use the --format=.. option.
62 -a URI
64 --add URI
65 Add a remote disk. See "ADDING REMOTE STORAGE" in guestfish(1).
66 --blocksize=512
68 --blocksize=4096
69 --blocksize
70 This parameter sets the sector size of the disk image. It affects
71 all explicitly added subsequent disks after this parameter. Using
72 --blocksize with no argument switches the disk sector size to the
73 default value which is usually 512 bytes. See also
74 "guestfs_add_drive_opts" in guestfs(3).
75 -c URI
77 --connect URI
78 If using libvirt, connect to the given URI. If omitted, then we
79 connect to the default libvirt hypervisor.
80 If you specify guest block devices directly (-a), then libvirt is
82 not used at all.
83 -d guest
85 --domain guest
86 Add all the disks from the named libvirt guest. Domain UUIDs can
87 be used instead of names.
88 --echo-keys
90 When prompting for keys and passphrases, virt-cat normally turns
91 echoing off so you cannot see what you are typing. If you are not
92 worried about Tempest attacks and there is no one else in the room
93 you can specify this flag to see what you are typing.
94 --format=raw|qcow2|..
96 --format
97 The default for the -a option is to auto-detect the format of the
98 disk image. Using this forces the disk format for -a options which
99 follow on the command line. Using --format with no argument
100 switches back to auto-detection for subsequent -a options.
101 For example:
103 virt-cat --format=raw -a disk.img file
105 forces raw format (no auto-detection) for disk.img.
107 virt-cat --format=raw -a disk.img --format -a another.img file
109 forces raw format (no auto-detection) for disk.img and reverts to
111 auto-detection for another.img.
112 If you have untrusted raw-format guest disk images, you should use
114 this option to specify the disk format. This avoids a possible
115 security problem with malicious guests (CVE-2010-3851).
116 --key SELECTOR
118 Specify a key for LUKS, to automatically open a LUKS device when
119 using the inspection. "ID" can be either the libguestfs device
120 name, or the UUID of the LUKS device.
121 --key "ID":key:KEY_STRING
123 Use the specified "KEY_STRING" as passphrase.
124 --key "ID":file:FILENAME
126 Read the passphrase from FILENAME.
127 --keys-from-stdin
129 Read key or passphrase parameters from stdin. The default is to
130 try to read passphrases from the user by opening /dev/tty.
131 If there are multiple encrypted devices then you may need to supply
133 multiple keys on stdin, one per line.
134 -m dev[:mountpoint[:options[:fstype]]]
136 --mount dev[:mountpoint[:options[:fstype]]]
137 Mount the named partition or logical volume on the given
138 mountpoint.
139 If the mountpoint is omitted, it defaults to /.
141 Specifying any mountpoint disables the inspection of the guest and
143 the mount of its root and all of its mountpoints, so make sure to
144 mount all the mountpoints needed to work with the filenames given
145 as arguments.
146 If you don’t know what filesystems a disk image contains, you can
148 either run guestfish without this option, then list the partitions,
149 filesystems and LVs available (see "list-partitions", "list-
150 filesystems" and "lvs" commands), or you can use the
151 virt-filesystems(1) program.
152 The third (and rarely used) part of the mount parameter is the list
154 of mount options used to mount the underlying filesystem. If this
155 is not given, then the mount options are either the empty string or
156 "ro" (the latter if the --ro flag is used). By specifying the
157 mount options, you override this default choice. Probably the only
158 time you would use this is to enable ACLs and/or extended
159 attributes if the filesystem can support them:
160 -m /dev/sda1:/:acl,user_xattr
162 Using this flag is equivalent to using the "mount-options" command.
164 The fourth part of the parameter is the filesystem driver to use,
166 such as "ext3" or "ntfs". This is rarely needed, but can be useful
167 if multiple drivers are valid for a filesystem (eg: "ext2" and
168 "ext3"), or if libguestfs misidentifies a filesystem.
169 -v
171 --verbose
172 Enable verbose messages for debugging.
173 -V
175 --version
176 Display version number and exit.
177 -x Enable tracing of libguestfs API calls.
179
181 Previous versions of virt-cat allowed you to write either:
182 virt-cat disk.img [disk.img ...] file
184 or
186 virt-cat guestname file
188 whereas in this version you should use -a or -d respectively to avoid
190 the confusing case where a disk image might have the same name as a
191 guest.
192 For compatibility the old style is still supported.
194
196 To list out the log files from guests, see the related tool
197 virt-log(1). It understands binary log formats such as the systemd
198 journal.
199 To follow (tail) text log files, use virt-tail(1).
201
203 "virt-cat" has a limited ability to understand Windows drive letters
204 and paths (eg. E:\foo\bar.txt).
205 If and only if the guest is running Windows then:
207 · Drive letter prefixes like "C:" are resolved against the Windows
209 Registry to the correct filesystem.
210 · Any backslash ("\") characters in the path are replaced with
212 forward slashes so that libguestfs can process it.
213 · The path is resolved case insensitively to locate the file that
215 should be displayed.
216 There are some known shortcomings:
218 · Some NTFS symbolic links may not be followed correctly.
220 · NTFS junction points that cross filesystems are not followed.
222
224 guestfish(1) is a more powerful, lower level tool which you can use
225 when "virt-cat" doesn't work.
226 Using "virt-cat" is approximately equivalent to doing:
228 guestfish --ro -i -d domname download file -
230 where "domname" is the name of the libvirt guest, and "file" is the
232 full path to the file. Note the final "-" (meaning "output to
233 stdout").
234 The command above uses libguestfs’s guest inspection feature and so
236 does not work on guests that libguestfs cannot inspect, or on things
237 like arbitrary disk images that don't contain guests. To display a
238 file from a disk image directly, use:
239 guestfish --ro -a disk.img -m /dev/sda1 download file -
241 where disk.img is the disk image, /dev/sda1 is the filesystem within
243 the disk image, and "file" is the full path to the file.
244
246 This program returns 0 if successful, or non-zero if there was an
247 error.
248
250 guestfs(3), guestfish(1), virt-copy-out(1), virt-edit(1), virt-log(1),
251 virt-tail(1), virt-tar-out(1), http://libguestfs.org/.
252
254 Richard W.M. Jones http://people.redhat.com/~rjones/
255
257 Copyright (C) 2010-2012 Red Hat Inc.
258
260 This program is free software; you can redistribute it and/or modify it
261 under the terms of the GNU General Public License as published by the
262 Free Software Foundation; either version 2 of the License, or (at your
263 option) any later version.
264 This program is distributed in the hope that it will be useful, but
266 WITHOUT ANY WARRANTY; without even the implied warranty of
267 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
268 General Public License for more details.
269 You should have received a copy of the GNU General Public License along
271 with this program; if not, write to the Free Software Foundation, Inc.,
272 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
273
275 To get a list of bugs against libguestfs, use this link:
276 https://bugzilla.redhat.com/buglist.cgi?component=libguestfs&product=Virtualization+Tools
277 To report a new bug against libguestfs, use this link:
279 https://bugzilla.redhat.com/enter_bug.cgi?component=libguestfs&product=Virtualization+Tools
280 When reporting a bug, please supply:
282 · The version of libguestfs.
284 · Where you got libguestfs (eg. which Linux distro, compiled from
286 source, etc)
287 · Describe the bug accurately and give a way to reproduce it.
289 · Run libguestfs-test-tool(1) and paste the complete, unedited output
291 into the bug report.
292libguestfs-1.44.0 2021-01-05 virt-cat(1)