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.
120 --key NAME:key:KEY_STRING
122 --key UUID:key:KEY_STRING
123 --key all:key:KEY_STRING
124 "NAME" is the libguestfs device name (eg. "/dev/sda1"). "UUID"
125 is the device UUID. "all" means try the key against any
126 encrypted device.
127 Use the specified "KEY_STRING" as passphrase.
129 --key NAME:file:FILENAME
131 --key UUID:file:FILENAME
132 --key all:file:FILENAME
133 Read the passphrase from FILENAME.
134 --key NAME:clevis
136 --key UUID:clevis
137 --key all:clevis
138 Attempt passphrase-less unlocking for the device with Clevis,
139 over the network. Please refer to "ENCRYPTED DISKS" in
140 guestfs(3) for more information on network-bound disk
141 encryption (NBDE).
142 Note that if any such option is present on the command line,
144 QEMU user networking will be automatically enabled for the
145 libguestfs appliance.
146 --keys-from-stdin
148 Read key or passphrase parameters from stdin. The default is to
149 try to read passphrases from the user by opening /dev/tty.
150 If there are multiple encrypted devices then you may need to supply
152 multiple keys on stdin, one per line.
153 -m dev[:mountpoint[:options[:fstype]]]
155 --mount dev[:mountpoint[:options[:fstype]]]
156 Mount the named partition or logical volume on the given
157 mountpoint.
158 If the mountpoint is omitted, it defaults to /.
160 Specifying any mountpoint disables the inspection of the guest and
162 the mount of its root and all of its mountpoints, so make sure to
163 mount all the mountpoints needed to work with the filenames given
164 as arguments.
165 If you don’t know what filesystems a disk image contains, you can
167 either run guestfish without this option, then list the partitions,
168 filesystems and LVs available (see "list-partitions", "list-
169 filesystems" and "lvs" commands), or you can use the
170 virt-filesystems(1) program.
171 The third (and rarely used) part of the mount parameter is the list
173 of mount options used to mount the underlying filesystem. If this
174 is not given, then the mount options are either the empty string or
175 "ro" (the latter if the --ro flag is used). By specifying the
176 mount options, you override this default choice. Probably the only
177 time you would use this is to enable ACLs and/or extended
178 attributes if the filesystem can support them:
179 -m /dev/sda1:/:acl,user_xattr
181 Using this flag is equivalent to using the "mount-options" command.
183 The fourth part of the parameter is the filesystem driver to use,
185 such as "ext3" or "ntfs". This is rarely needed, but can be useful
186 if multiple drivers are valid for a filesystem (eg: "ext2" and
187 "ext3"), or if libguestfs misidentifies a filesystem.
188 -v
190 --verbose
191 Enable verbose messages for debugging.
192 -V
194 --version
195 Display version number and exit.
196 -x Enable tracing of libguestfs API calls.
198
200 Previous versions of virt-cat allowed you to write either:
201 virt-cat disk.img [disk.img ...] file
203 or
205 virt-cat guestname file
207 whereas in this version you should use -a or -d respectively to avoid
209 the confusing case where a disk image might have the same name as a
210 guest.
211 For compatibility the old style is still supported.
213
215 To list out the log files from guests, see the related tool
216 virt-log(1). It understands binary log formats such as the systemd
217 journal.
218 To follow (tail) text log files, use virt-tail(1).
220
222 "virt-cat" has a limited ability to understand Windows drive letters
223 and paths (eg. E:\foo\bar.txt).
224 If and only if the guest is running Windows then:
226 • Drive letter prefixes like "C:" are resolved against the Windows
228 Registry to the correct filesystem.
229 • Any backslash ("\") characters in the path are replaced with
231 forward slashes so that libguestfs can process it.
232 • The path is resolved case insensitively to locate the file that
234 should be displayed.
235 There are some known shortcomings:
237 • Some NTFS symbolic links may not be followed correctly.
239 • NTFS junction points that cross filesystems are not followed.
241
243 guestfish(1) is a more powerful, lower level tool which you can use
244 when "virt-cat" doesn't work.
245 Using "virt-cat" is approximately equivalent to doing:
247 guestfish --ro -i -d domname download file -
249 where "domname" is the name of the libvirt guest, and "file" is the
251 full path to the file. Note the final "-" (meaning "output to
252 stdout").
253 The command above uses libguestfs’s guest inspection feature and so
255 does not work on guests that libguestfs cannot inspect, or on things
256 like arbitrary disk images that don't contain guests. To display a
257 file from a disk image directly, use:
258 guestfish --ro -a disk.img -m /dev/sda1 download file -
260 where disk.img is the disk image, /dev/sda1 is the filesystem within
262 the disk image, and "file" is the full path to the file.
263
265 This program returns 0 if successful, or non-zero if there was an
266 error.
267
269 guestfs(3), guestfish(1), virt-copy-out(1), virt-edit(1), virt-log(1),
270 virt-tail(1), virt-tar-out(1), http://libguestfs.org/.
271
273 Richard W.M. Jones http://people.redhat.com/~rjones/
274
276 Copyright (C) 2010-2023 Red Hat Inc.
277
279 This program is free software; you can redistribute it and/or modify it
280 under the terms of the GNU General Public License as published by the
281 Free Software Foundation; either version 2 of the License, or (at your
282 option) any later version.
283 This program is distributed in the hope that it will be useful, but
285 WITHOUT ANY WARRANTY; without even the implied warranty of
286 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
287 General Public License for more details.
288 You should have received a copy of the GNU General Public License along
290 with this program; if not, write to the Free Software Foundation, Inc.,
291 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
292
294 To get a list of bugs against libguestfs, use this link:
295 https://bugzilla.redhat.com/buglist.cgi?component=libguestfs&product=Virtualization+Tools
296 To report a new bug against libguestfs, use this link:
298 https://bugzilla.redhat.com/enter_bug.cgi?component=libguestfs&product=Virtualization+Tools
299 When reporting a bug, please supply:
301 • The version of libguestfs.
303 • Where you got libguestfs (eg. which Linux distro, compiled from
305 source, etc)
306 • Describe the bug accurately and give a way to reproduce it.
308 • Run libguestfs-test-tool(1) and paste the complete, unedited output
310 into the bug report.
311guestfs-tools-1.51.6 2023-12-09 virt-cat(1)