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 If there are multiple encrypted devices then you may need to supply
167 multiple keys on stdin, one per line.
168 -m dev[:mountpoint[:options[:fstype]]]
170 --mount dev[:mountpoint[:options[:fstype]]]
171 Mount the named partition or logical volume on the given
172 mountpoint.
173 If the mountpoint is omitted, it defaults to /.
175 Specifying any mountpoint disables the inspection of the guest and
177 the mount of its root and all of its mountpoints, so make sure to
178 mount all the mountpoints needed to work with the filenames given
179 as arguments.
180 If you don’t know what filesystems a disk image contains, you can
182 either run guestfish without this option, then list the partitions,
183 filesystems and LVs available (see "list-partitions", "list-
184 filesystems" and "lvs" commands), or you can use the
185 virt-filesystems(1) program.
186 The third (and rarely used) part of the mount parameter is the list
188 of mount options used to mount the underlying filesystem. If this
189 is not given, then the mount options are either the empty string or
190 "ro" (the latter if the --ro flag is used). By specifying the
191 mount options, you override this default choice. Probably the only
192 time you would use this is to enable ACLs and/or extended
193 attributes if the filesystem can support them:
194 -m /dev/sda1:/:acl,user_xattr
196 Using this flag is equivalent to using the "mount-options" command.
198 The fourth part of the parameter is the filesystem driver to use,
200 such as "ext3" or "ntfs". This is rarely needed, but can be useful
201 if multiple drivers are valid for a filesystem (eg: "ext2" and
202 "ext3"), or if libguestfs misidentifies a filesystem.
203 -v
205 --verbose
206 Enable verbose messages for debugging.
207 -V
209 --version
210 Display version number and exit.
211 -x Enable tracing of libguestfs API calls.
213
215 Previous versions of virt-edit allowed you to write either:
216 virt-edit disk.img [disk.img ...] file
218 or
220 virt-edit guestname file
222 whereas in this version you should use -a or -d respectively to avoid
224 the confusing case where a disk image might have the same name as a
225 guest.
226 For compatibility the old style is still supported.
228
230 "virt-edit" normally calls out to $EDITOR (or vi) so the system
231 administrator can interactively edit the file.
232 There are two ways also to use "virt-edit" from scripts in order to
234 make automated edits to files. (Note that although you can use
235 "virt-edit" like this, it’s less error-prone to write scripts directly
236 using the libguestfs API and Augeas for configuration file editing.)
237 The first method is to temporarily set $EDITOR to any script or program
239 you want to run. The script is invoked as "$EDITOR tmpfile" and it
240 should update "tmpfile" in place however it likes.
241 The second method is to use the -e parameter of "virt-edit" to run a
243 short Perl snippet in the style of sed(1). For example to replace all
244 instances of "foo" with "bar" in a file:
245 virt-edit -d domname filename -e 's/foo/bar/'
247 The full power of Perl regular expressions can be used (see perlre(1)).
249 For example to delete root’s password you could do:
250 virt-edit -d domname /etc/passwd -e 's/^root:.*?:/root::/'
252 What really happens is that the snippet is evaluated as a Perl
254 expression for each line of the file. The line, including the final
255 "\n", is passed in $_ and the expression should update $_ or leave it
256 unchanged.
257 To delete a line, set $_ to the empty string. For example, to delete
259 the "apache" user account from the password file you can do:
260 virt-edit -d mydomain /etc/passwd -e '$_ = "" if /^apache:/'
262 To insert a line, prepend or append it to $_. However appending lines
264 to the end of the file is rather difficult this way since there is no
265 concept of "last line of the file" - your expression just doesn't get
266 called again. You might want to use the first method (setting $EDITOR)
267 if you want to do this.
268 The variable $lineno contains the current line number. As is
270 traditional, the first line in the file is number 1.
271 The return value from the expression is ignored, but the expression may
273 call "die" in order to abort the whole program, leaving the original
274 file untouched.
275 Remember when matching the end of a line that $_ may contain the final
277 "\n", or (for DOS files) "\r\n", or if the file does not end with a
278 newline then neither of these. Thus to match or substitute some text
279 at the end of a line, use this regular expression:
280 /some text(\r?\n)?$/
282 Alternately, use the perl "chomp" function, being careful not to chomp
284 $_ itself (since that would remove all newlines from the file):
285 my $m = $_; chomp $m; $m =~ /some text$/
287
289 "virt-edit" has a limited ability to understand Windows drive letters
290 and paths (eg. E:\foo\bar.txt).
291 If and only if the guest is running Windows then:
293 • Drive letter prefixes like "C:" are resolved against the Windows
295 Registry to the correct filesystem.
296 • Any backslash ("\") characters in the path are replaced with
298 forward slashes so that libguestfs can process it.
299 • The path is resolved case insensitively to locate the file that
301 should be edited.
302 There are some known shortcomings:
304 • Some NTFS symbolic links may not be followed correctly.
306 • NTFS junction points that cross filesystems are not followed.
308
310 guestfish(1) is a more powerful, lower level tool which you can use
311 when "virt-edit" doesn't work.
312 Using "virt-edit" is approximately equivalent to doing:
314 guestfish --rw -i -d domname edit /file
316 where "domname" is the name of the libvirt guest, and /file is the full
318 path to the file.
319 The command above uses libguestfs’s guest inspection feature and so
321 does not work on guests that libguestfs cannot inspect, or on things
322 like arbitrary disk images that don't contain guests. To edit a file
323 on a disk image directly, use:
324 guestfish --rw -a disk.img -m /dev/sda1 edit /file
326 where disk.img is the disk image, /dev/sda1 is the filesystem within
328 the disk image to edit, and /file is the full path to the file.
329 "virt-edit" cannot create new files. Use the guestfish commands
331 "touch", "write" or "upload" instead:
332 guestfish --rw -i -d domname touch /newfile
334 guestfish --rw -i -d domname write /newfile "new content"
336 guestfish --rw -i -d domname upload localfile /newfile
338
340 "EDITOR"
341 If set, this string is used as the editor. It may contain
342 arguments, eg. "emacs -nw"
343 If not set, "vi" is used.
345
347 This program returns 0 if successful, or non-zero if there was an
348 error.
349
351 guestfs(3), guestfish(1), virt-cat(1), virt-copy-in(1), virt-tar-in(1),
352 http://libguestfs.org/, perl(1), perlre(1).
353
355 Richard W.M. Jones http://people.redhat.com/~rjones/
356
358 Copyright (C) 2009-2020 Red Hat Inc.
359
361 This program is free software; you can redistribute it and/or modify it
362 under the terms of the GNU General Public License as published by the
363 Free Software Foundation; either version 2 of the License, or (at your
364 option) any later version.
365 This program is distributed in the hope that it will be useful, but
367 WITHOUT ANY WARRANTY; without even the implied warranty of
368 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
369 General Public License for more details.
370 You should have received a copy of the GNU General Public License along
372 with this program; if not, write to the Free Software Foundation, Inc.,
373 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
374
376 To get a list of bugs against libguestfs, use this link:
377 https://bugzilla.redhat.com/buglist.cgi?component=libguestfs&product=Virtualization+Tools
378 To report a new bug against libguestfs, use this link:
380 https://bugzilla.redhat.com/enter_bug.cgi?component=libguestfs&product=Virtualization+Tools
381 When reporting a bug, please supply:
383 • The version of libguestfs.
385 • Where you got libguestfs (eg. which Linux distro, compiled from
387 source, etc)
388 • Describe the bug accurately and give a way to reproduce it.
390 • Run libguestfs-test-tool(1) and paste the complete, unedited output
392 into the bug report.
393guestfs-tools-1.46.1 2021-05-13 virt-edit(1)