1virt-edit(1)                Virtualization Support                virt-edit(1)
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3
4

NAME

6       virt-edit - Edit a file in a virtual machine
7

SYNOPSIS

9        virt-edit [--options] -d domname file [file ...]
10
11        virt-edit [--options] -a disk.img [-a disk.img ...] file [file ...]
12
13        virt-edit [-d domname|-a disk.img] file -e 'expr'
14
15       Old-style:
16
17        virt-edit domname file
18
19        virt-edit disk.img [disk.img ...] file
20

WARNING

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

DESCRIPTION

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
31       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
35       If you want to just view a file, use virt-cat(1).
36
37       For more complex cases you should look at the guestfish(1) tool (see
38       "USING GUESTFISH" below).
39
40       "virt-edit" cannot be used to create a new file.  guestfish(1) can do
41       that and much more.
42

EXAMPLES

44       Edit the named files interactively:
45
46        virt-edit -d mydomain /boot/grub/grub.conf
47
48        virt-edit -d mydomain /etc/passwd
49
50       For Windows guests, some Windows paths are understood:
51
52        virt-edit -d mywindomain 'c:\autoexec.bat'
53
54       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
58        virt-edit -d mydomain /etc/inittab -e 's/^id:.*/id:5:initdefault:/'
59

OPTIONS

61       --help
62           Display brief help.
63
64       -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
70           The format of the disk image is auto-detected.  To override this
71           and force a particular format use the --format=.. option.
72
73       -a URI
74       --add URI
75           Add a remote disk.  See "ADDING REMOTE STORAGE" in guestfish(1).
76
77       -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
82           Usually the first character of "extension" would be a dot "."  so
83           you would write:
84
85            virt-edit -b .orig [etc]
86
87           By default, no backup file is made.
88
89       --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
98       -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
103           If you specify guest block devices directly, then libvirt is not
104           used at all.
105
106       -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
111       --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
117       -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
124           Be careful to properly quote the expression to prevent it from
125           being altered by the shell.
126
127           Note that this option is only available when Perl 5 is installed.
128
129       --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
136           For example:
137
138            virt-edit --format=raw -a disk.img file
139
140           forces raw format (no auto-detection) for disk.img.
141
142            virt-edit --format=raw -a disk.img --format -a another.img file
143
144           forces raw format (no auto-detection) for disk.img and reverts to
145           auto-detection for another.img.
146
147           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
151       --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
156           --key "ID":key:KEY_STRING
157               Use the specified "KEY_STRING" as passphrase.
158
159           --key "ID":file:FILENAME
160               Read the passphrase from FILENAME.
161
162       --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
166           If there are multiple encrypted devices then you may need to supply
167           multiple keys on stdin, one per line.
168
169       -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
174           If the mountpoint is omitted, it defaults to /.
175
176           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
181           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
187           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
195            -m /dev/sda1:/:acl,user_xattr
196
197           Using this flag is equivalent to using the "mount-options" command.
198
199           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
204       -v
205       --verbose
206           Enable verbose messages for debugging.
207
208       -V
209       --version
210           Display version number and exit.
211
212       -x  Enable tracing of libguestfs API calls.
213

OLD-STYLE COMMAND LINE ARGUMENTS

215       Previous versions of virt-edit allowed you to write either:
216
217        virt-edit disk.img [disk.img ...] file
218
219       or
220
221        virt-edit guestname file
222
223       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
227       For compatibility the old style is still supported.
228

NON-INTERACTIVE EDITING

230       "virt-edit" normally calls out to $EDITOR (or vi) so the system
231       administrator can interactively edit the file.
232
233       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
238       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
242       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
246        virt-edit -d domname filename -e 's/foo/bar/'
247
248       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
251        virt-edit -d domname /etc/passwd -e 's/^root:.*?:/root::/'
252
253       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
258       To delete a line, set $_ to the empty string.  For example, to delete
259       the "apache" user account from the password file you can do:
260
261        virt-edit -d mydomain /etc/passwd -e '$_ = "" if /^apache:/'
262
263       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
269       The variable $lineno contains the current line number.  As is
270       traditional, the first line in the file is number 1.
271
272       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
276       Remember when matching the end of a line that $_ may contain the final
277       "\n", or (for DOS files) "\r\n", or if the file does not end with a
278       newline then neither of these.  Thus to match or substitute some text
279       at the end of a line, use this regular expression:
280
281        /some text(\r?\n)?$/
282
283       Alternately, use the perl "chomp" function, being careful not to chomp
284       $_ itself (since that would remove all newlines from the file):
285
286        my $m = $_; chomp $m; $m =~ /some text$/
287

WINDOWS PATHS

289       "virt-edit" has a limited ability to understand Windows drive letters
290       and paths (eg. E:\foo\bar.txt).
291
292       If and only if the guest is running Windows then:
293
294       •   Drive letter prefixes like "C:" are resolved against the Windows
295           Registry to the correct filesystem.
296
297       •   Any backslash ("\") characters in the path are replaced with
298           forward slashes so that libguestfs can process it.
299
300       •   The path is resolved case insensitively to locate the file that
301           should be edited.
302
303       There are some known shortcomings:
304
305       •   Some NTFS symbolic links may not be followed correctly.
306
307       •   NTFS junction points that cross filesystems are not followed.
308

USING GUESTFISH

310       guestfish(1) is a more powerful, lower level tool which you can use
311       when "virt-edit" doesn't work.
312
313       Using "virt-edit" is approximately equivalent to doing:
314
315        guestfish --rw -i -d domname edit /file
316
317       where "domname" is the name of the libvirt guest, and /file is the full
318       path to the file.
319
320       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
325        guestfish --rw -a disk.img -m /dev/sda1 edit /file
326
327       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
330       "virt-edit" cannot create new files.  Use the guestfish commands
331       "touch", "write" or "upload" instead:
332
333        guestfish --rw -i -d domname touch /newfile
334
335        guestfish --rw -i -d domname write /newfile "new content"
336
337        guestfish --rw -i -d domname upload localfile /newfile
338

ENVIRONMENT VARIABLES

340       "EDITOR"
341           If set, this string is used as the editor.  It may contain
342           arguments, eg. "emacs -nw"
343
344           If not set, "vi" is used.
345

EXIT STATUS

347       This program returns 0 if successful, or non-zero if there was an
348       error.
349

SEE ALSO

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

AUTHOR

355       Richard W.M. Jones http://people.redhat.com/~rjones/
356
358       Copyright (C) 2009-2020 Red Hat Inc.
359

LICENSE

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
366       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
371       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

BUGS

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
379       To report a new bug against libguestfs, use this link:
380       https://bugzilla.redhat.com/enter_bug.cgi?component=libguestfs&product=Virtualization+Tools
381
382       When reporting a bug, please supply:
383
384       •   The version of libguestfs.
385
386       •   Where you got libguestfs (eg. which Linux distro, compiled from
387           source, etc)
388
389       •   Describe the bug accurately and give a way to reproduce it.
390
391       •   Run libguestfs-test-tool(1) and paste the complete, unedited output
392           into the bug report.
393
394
395
396guestfs-tools-1.47.2              2021-07-22                      virt-edit(1)
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