1virt-edit(1) Virtualization Support virt-edit(1)
2
6 virt-edit - Edit a file in a virtual machine
7
9 virt-edit [--options] -d domname file [file ...]
10 virt-edit [--options] -a disk.img [-a disk.img ...] file [file ...]
12 virt-edit [-d domname|-a disk.img] file -e 'expr'
14 Old-style:
16 virt-edit domname file
18 virt-edit disk.img [disk.img ...] file
20
22 Using "virt-edit" on live virtual machines, or concurrently with other
23 disk editing tools, can be dangerous, potentially causing disk
24 corruption. The virtual machine must be shut down before you use this
25 command, and disk images must not be edited concurrently.
26
28 "virt-edit" is a command line tool to edit "file" where each "file"
29 exists in the named virtual machine (or disk image).
30 Multiple filenames can be given, in which case they are each edited in
32 turn. Each filename must be a full path, starting at the root
33 directory (starting with '/').
34 If you want to just view a file, use virt-cat(1).
36 For more complex cases you should look at the guestfish(1) tool (see
38 "USING GUESTFISH" below).
39 "virt-edit" cannot be used to create a new file. guestfish(1) can do
41 that and much more.
42
44 Edit the named files interactively:
45 virt-edit -d mydomain /boot/grub/grub.conf
47 virt-edit -d mydomain /etc/passwd
49 For Windows guests, some Windows paths are understood:
51 virt-edit -d mywindomain 'c:\autoexec.bat'
53 If Perl is installed, you can also edit files non-interactively (see
55 "NON-INTERACTIVE EDITING" below). To change the init default level to
56 5:
57 virt-edit -d mydomain /etc/inittab -e 's/^id:.*/id:5:initdefault:/'
59
61 --help
62 Display brief help.
63 -a file
65 --add file
66 Add file which should be a disk image from a virtual machine. If
67 the virtual machine has multiple block devices, you must supply all
68 of them with separate -a options.
69 The format of the disk image is auto-detected. To override this
71 and force a particular format use the --format=.. option.
72 -a URI
74 --add URI
75 Add a remote disk. See "ADDING REMOTE STORAGE" in guestfish(1).
76 -b EXTENSION
78 --backup EXTENSION
79 Create a backup of the original file in the guest disk image. The
80 backup has the original filename with "extension" added.
81 Usually the first character of "extension" would be a dot "." so
83 you would write:
84 virt-edit -b .orig [etc]
86 By default, no backup file is made.
88 --blocksize=512
90 --blocksize=4096
91 --blocksize
92 This parameter sets the sector size of the disk image. It affects
93 all explicitly added subsequent disks after this parameter. Using
94 --blocksize with no argument switches the disk sector size to the
95 default value which is usually 512 bytes. See also
96 "guestfs_add_drive_opts" in guestfs(3).
97 -c URI
99 --connect URI
100 If using libvirt, connect to the given URI. If omitted, then we
101 connect to the default libvirt hypervisor.
102 If you specify guest block devices directly, then libvirt is not
104 used at all.
105 -d GUEST
107 --domain GUEST
108 Add all the disks from the named libvirt guest. Domain UUIDs can
109 be used instead of names.
110 --echo-keys
112 When prompting for keys and passphrases, virt-edit normally turns
113 echoing off so you cannot see what you are typing. If you are not
114 worried about Tempest attacks and there is no one else in the room
115 you can specify this flag to see what you are typing.
116 -e EXPR
118 --edit EXPR
119 --expr EXPR
120 Instead of launching the external editor, non-interactively apply
121 the Perl expression "EXPR" to each line in the file. See "NON-
122 INTERACTIVE EDITING" below.
123 Be careful to properly quote the expression to prevent it from
125 being altered by the shell.
126 Note that this option is only available when Perl 5 is installed.
128 --format=raw|qcow2|..
130 --format
131 The default for the -a option is to auto-detect the format of the
132 disk image. Using this forces the disk format for -a options which
133 follow on the command line. Using --format with no argument
134 switches back to auto-detection for subsequent -a options.
135 For example:
137 virt-edit --format=raw -a disk.img file
139 forces raw format (no auto-detection) for disk.img.
141 virt-edit --format=raw -a disk.img --format -a another.img file
143 forces raw format (no auto-detection) for disk.img and reverts to
145 auto-detection for another.img.
146 If you have untrusted raw-format guest disk images, you should use
148 this option to specify the disk format. This avoids a possible
149 security problem with malicious guests (CVE-2010-3851).
150 --key SELECTOR
152 Specify a key for LUKS, to automatically open a LUKS device when
153 using the inspection. "ID" can be either the libguestfs device
154 name, or the UUID of the LUKS device.
155 --key "ID":key:KEY_STRING
157 Use the specified "KEY_STRING" as passphrase.
158 --key "ID":file:FILENAME
160 Read the passphrase from FILENAME.
161 --keys-from-stdin
163 Read key or passphrase parameters from stdin. The default is to
164 try to read passphrases from the user by opening /dev/tty.
165 -m dev[:mountpoint[:options[:fstype]]]
167 --mount dev[:mountpoint[:options[:fstype]]]
168 Mount the named partition or logical volume on the given
169 mountpoint.
170 If the mountpoint is omitted, it defaults to /.
172 Specifying any mountpoint disables the inspection of the guest and
174 the mount of its root and all of its mountpoints, so make sure to
175 mount all the mountpoints needed to work with the filenames given
176 as arguments.
177 If you don’t know what filesystems a disk image contains, you can
179 either run guestfish without this option, then list the partitions,
180 filesystems and LVs available (see "list-partitions", "list-
181 filesystems" and "lvs" commands), or you can use the
182 virt-filesystems(1) program.
183 The third (and rarely used) part of the mount parameter is the list
185 of mount options used to mount the underlying filesystem. If this
186 is not given, then the mount options are either the empty string or
187 "ro" (the latter if the --ro flag is used). By specifying the
188 mount options, you override this default choice. Probably the only
189 time you would use this is to enable ACLs and/or extended
190 attributes if the filesystem can support them:
191 -m /dev/sda1:/:acl,user_xattr
193 Using this flag is equivalent to using the "mount-options" command.
195 The fourth part of the parameter is the filesystem driver to use,
197 such as "ext3" or "ntfs". This is rarely needed, but can be useful
198 if multiple drivers are valid for a filesystem (eg: "ext2" and
199 "ext3"), or if libguestfs misidentifies a filesystem.
200 -v
202 --verbose
203 Enable verbose messages for debugging.
204 -V
206 --version
207 Display version number and exit.
208 -x Enable tracing of libguestfs API calls.
210
212 Previous versions of virt-edit allowed you to write either:
213 virt-edit disk.img [disk.img ...] file
215 or
217 virt-edit guestname file
219 whereas in this version you should use -a or -d respectively to avoid
221 the confusing case where a disk image might have the same name as a
222 guest.
223 For compatibility the old style is still supported.
225
227 "virt-edit" normally calls out to $EDITOR (or vi) so the system
228 administrator can interactively edit the file.
229 There are two ways also to use "virt-edit" from scripts in order to
231 make automated edits to files. (Note that although you can use
232 "virt-edit" like this, it’s less error-prone to write scripts directly
233 using the libguestfs API and Augeas for configuration file editing.)
234 The first method is to temporarily set $EDITOR to any script or program
236 you want to run. The script is invoked as "$EDITOR tmpfile" and it
237 should update "tmpfile" in place however it likes.
238 The second method is to use the -e parameter of "virt-edit" to run a
240 short Perl snippet in the style of sed(1). For example to replace all
241 instances of "foo" with "bar" in a file:
242 virt-edit -d domname filename -e 's/foo/bar/'
244 The full power of Perl regular expressions can be used (see perlre(1)).
246 For example to delete root’s password you could do:
247 virt-edit -d domname /etc/passwd -e 's/^root:.*?:/root::/'
249 What really happens is that the snippet is evaluated as a Perl
251 expression for each line of the file. The line, including the final
252 "\n", is passed in $_ and the expression should update $_ or leave it
253 unchanged.
254 To delete a line, set $_ to the empty string. For example, to delete
256 the "apache" user account from the password file you can do:
257 virt-edit -d mydomain /etc/passwd -e '$_ = "" if /^apache:/'
259 To insert a line, prepend or append it to $_. However appending lines
261 to the end of the file is rather difficult this way since there is no
262 concept of "last line of the file" - your expression just doesn't get
263 called again. You might want to use the first method (setting $EDITOR)
264 if you want to do this.
265 The variable $lineno contains the current line number. As is
267 traditional, the first line in the file is number 1.
268 The return value from the expression is ignored, but the expression may
270 call "die" in order to abort the whole program, leaving the original
271 file untouched.
272 Remember when matching the end of a line that $_ may contain the final
274 "\n", or (for DOS files) "\r\n", or if the file does not end with a
275 newline then neither of these. Thus to match or substitute some text
276 at the end of a line, use this regular expression:
277 /some text(\r?\n)?$/
279 Alternately, use the perl "chomp" function, being careful not to chomp
281 $_ itself (since that would remove all newlines from the file):
282 my $m = $_; chomp $m; $m =~ /some text$/
284
286 "virt-edit" has a limited ability to understand Windows drive letters
287 and paths (eg. E:\foo\bar.txt).
288 If and only if the guest is running Windows then:
290 · Drive letter prefixes like "C:" are resolved against the Windows
292 Registry to the correct filesystem.
293 · Any backslash ("\") characters in the path are replaced with
295 forward slashes so that libguestfs can process it.
296 · The path is resolved case insensitively to locate the file that
298 should be edited.
299 There are some known shortcomings:
301 · Some NTFS symbolic links may not be followed correctly.
303 · NTFS junction points that cross filesystems are not followed.
305
307 guestfish(1) is a more powerful, lower level tool which you can use
308 when "virt-edit" doesn't work.
309 Using "virt-edit" is approximately equivalent to doing:
311 guestfish --rw -i -d domname edit /file
313 where "domname" is the name of the libvirt guest, and /file is the full
315 path to the file.
316 The command above uses libguestfs’s guest inspection feature and so
318 does not work on guests that libguestfs cannot inspect, or on things
319 like arbitrary disk images that don't contain guests. To edit a file
320 on a disk image directly, use:
321 guestfish --rw -a disk.img -m /dev/sda1 edit /file
323 where disk.img is the disk image, /dev/sda1 is the filesystem within
325 the disk image to edit, and /file is the full path to the file.
326 "virt-edit" cannot create new files. Use the guestfish commands
328 "touch", "write" or "upload" instead:
329 guestfish --rw -i -d domname touch /newfile
331 guestfish --rw -i -d domname write /newfile "new content"
333 guestfish --rw -i -d domname upload localfile /newfile
335
337 "EDITOR"
338 If set, this string is used as the editor. It may contain
339 arguments, eg. "emacs -nw"
340 If not set, "vi" is used.
342
344 This program returns 0 if successful, or non-zero if there was an
345 error.
346
348 guestfs(3), guestfish(1), virt-cat(1), virt-copy-in(1), virt-tar-in(1),
349 http://libguestfs.org/, perl(1), perlre(1).
350
352 Richard W.M. Jones http://people.redhat.com/~rjones/
353
355 Copyright (C) 2009-2020 Red Hat Inc.
356
358 This program is free software; you can redistribute it and/or modify it
359 under the terms of the GNU General Public License as published by the
360 Free Software Foundation; either version 2 of the License, or (at your
361 option) any later version.
362 This program is distributed in the hope that it will be useful, but
364 WITHOUT ANY WARRANTY; without even the implied warranty of
365 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
366 General Public License for more details.
367 You should have received a copy of the GNU General Public License along
369 with this program; if not, write to the Free Software Foundation, Inc.,
370 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
371
373 To get a list of bugs against libguestfs, use this link:
374 https://bugzilla.redhat.com/buglist.cgi?component=libguestfs&product=Virtualization+Tools
375 To report a new bug against libguestfs, use this link:
377 https://bugzilla.redhat.com/enter_bug.cgi?component=libguestfs&product=Virtualization+Tools
378 When reporting a bug, please supply:
380 · The version of libguestfs.
382 · Where you got libguestfs (eg. which Linux distro, compiled from
384 source, etc)
385 · Describe the bug accurately and give a way to reproduce it.
387 · Run libguestfs-test-tool(1) and paste the complete, unedited output
389 into the bug report.
390libguestfs-1.42.0 2020-03-09 virt-edit(1)