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

NAME
       virt-edit - Edit a file in a virtual machine

SYNOPSIS
	virt-edit [--options] -d domname file [file ...]

	virt-edit [--options] -a disk.img [-a disk.img ...] file [file ...]

	virt-edit [-d domname|-a disk.img] file -e 'expr'

       Old-style:

	virt-edit domname file

	virt-edit disk.img [disk.img ...] file

WARNING
       You must not use "virt-edit" on live virtual machines.  If you do this, you risk disk
       corruption in the VM.  "virt-edit" tries to stop you from doing this, but doesn't catch
       all cases.

DESCRIPTION
       "virt-edit" is a command line tool to edit "file" where each "file" exists in the named
       virtual machine (or disk image).

       Multiple filenames can be given, in which case they are each edited in turn.  Each
       filename must be a full path, starting at the root directory (starting with '/').

       If you want to just view a file, use virt-cat(1).

       For more complex cases you should look at the guestfish(1) tool (see "USING GUESTFISH"
       below).

       "virt-edit" cannot be used to create a new file.  guestfish(1) can do that and much more.

EXAMPLES
       Edit the named files interactively:

	virt-edit -d mydomain /boot/grub/grub.conf

	virt-edit -d mydomain /etc/passwd

       For Windows guests, some Windows paths are understood:

	virt-edit -d mywindomain 'c:\autoexec.bat'

       If Perl is installed, you can also edit files non-interactively (see "NON-INTERACTIVE
       EDITING" below).  To change the init default level to 5:

	virt-edit -d mydomain /etc/inittab -e 's/^id:.*/id:5:initdefault:/'

OPTIONS
       --help
	   Display brief help.

       -a file
       --add file
	   Add file which should be a disk image from a virtual machine.  If the virtual machine
	   has multiple block devices, you must supply all of them with separate -a options.

	   The format of the disk image is auto-detected.  To override this and force a
	   particular format use the --format=.. option.

       -a URI
       --add URI
	   Add a remote disk.  See "ADDING REMOTE STORAGE" in guestfish(1).

       -b extension
       --backup extension
	   Create a backup of the original file in the guest disk image.  The backup has the
	   original filename with "extension" added.

	   Usually the first character of "extension" would be a dot "."  so you would write:

	    virt-edit -b .orig [etc]

	   By default, no backup file is made.

       -c URI
       --connect URI
	   If using libvirt, connect to the given URI.	If omitted, then we connect to the
	   default libvirt hypervisor.

	   If you specify guest block devices directly, then libvirt is not used at all.

       -d guest
       --domain guest
	   Add all the disks from the named libvirt guest.  Domain UUIDs can be used instead of
	   names.

       --echo-keys
	   When prompting for keys and passphrases, virt-edit normally turns echoing off so you
	   cannot see what you are typing.  If you are not worried about Tempest attacks and
	   there is no one else in the room you can specify this flag to see what you are typing.

       -e EXPR
       --expr EXPR
	   Instead of launching the external editor, non-interactively apply the Perl expression
	   "EXPR" to each line in the file.  See "NON-INTERACTIVE EDITING" below.

	   Be careful to properly quote the expression to prevent it from being altered by the
	   shell.

	   Note that this option is only available when Perl 5 is installed.

       --format raw|qcow2|...
       --format
	   The default for the -a option is to auto-detect the format of the disk image.  Using
	   this forces the disk format for -a options which follow on the command line.  Using
	   --format with no argument switches back to auto-detection for subsequent -a options.

	   For example:

	    virt-edit --format=raw -a disk.img file

	   forces raw format (no auto-detection) for "disk.img".

	    virt-edit --format=raw -a disk.img --format -a another.img file

	   forces raw format (no auto-detection) for "disk.img" and reverts to auto-detection for
	   "another.img".

	   If you have untrusted raw-format guest disk images, you should use this option to
	   specify the disk format.  This avoids a possible security problem with malicious
	   guests (CVE-2010-3851).

       --keys-from-stdin
	   Read key or passphrase parameters from stdin.  The default is to try to read
	   passphrases from the user by opening "/dev/tty".

       -v
       --verbose
	   Enable verbose messages for debugging.

       -V
       --version
	   Display version number and exit.

       -x  Enable tracing of libguestfs API calls.

OLD-STYLE COMMAND LINE ARGUMENTS
       Previous versions of virt-edit allowed you to write either:

	virt-edit disk.img [disk.img ...] file

       or

	virt-edit guestname file

       whereas in this version you should use -a or -d respectively to avoid the confusing case
       where a disk image might have the same name as a guest.

       For compatibility the old style is still supported.

NON-INTERACTIVE EDITING
       "virt-edit" normally calls out to $EDITOR (or vi) so the system administrator can
       interactively edit the file.

       There are two ways also to use "virt-edit" from scripts in order to make automated edits
       to files.  (Note that although you can use "virt-edit" like this, it's less error-prone to
       write scripts directly using the libguestfs API and Augeas for configuration file
       editing.)

       The first method is to temporarily set $EDITOR to any script or program you want to run.
       The script is invoked as "$EDITOR tmpfile" and it should update "tmpfile" in place however
       it likes.

       The second method is to use the -e parameter of "virt-edit" to run a short Perl snippet in
       the style of sed(1).  For example to replace all instances of "foo" with "bar" in a file:

	virt-edit -d domname filename -e 's/foo/bar/'

       The full power of Perl regular expressions can be used (see perlre(1)).	For example to
       delete root's password you could do:

	virt-edit -d domname /etc/passwd -e 's/^root:.*?:/root::/'

       What really happens is that the snippet is evaluated as a Perl expression for each line of
       the file.  The line, including the final "\n", is passed in $_ and the expression should
       update $_ or leave it unchanged.

       To delete a line, set $_ to the empty string.  For example, to delete the "apache" user
       account from the password file you can do:

	virt-edit -d mydomain /etc/passwd -e '$_ = "" if /^apache:/'

       To insert a line, prepend or append it to $_.  However appending lines to the end of the
       file is rather difficult this way since there is no concept of "last line of the file" -
       your expression just doesn't get called again.  You might want to use the first method
       (setting $EDITOR) if you want to do this.

       The variable $lineno contains the current line number.  As is traditional, the first line
       in the file is number 1.

       The return value from the expression is ignored, but the expression may call "die" in
       order to abort the whole program, leaving the original file untouched.

       Remember when matching the end of a line that $_ may contain the final "\n", or (for DOS
       files) "\r\n", or if the file does not end with a newline then neither of these.  Thus to
       match or substitute some text at the end of a line, use this regular expression:

	/some text(\r?\n)?$/

       Alternately, use the perl "chomp" function, being careful not to chomp $_ itself (since
       that would remove all newlines from the file):

	my $m = $_; chomp $m; $m =~ /some text$/

WINDOWS PATHS
       "virt-edit" has a limited ability to understand Windows drive letters and paths (eg.
       "E:\foo\bar.txt").

       If and only if the guest is running Windows then:

       o   Drive letter prefixes like "C:" are resolved against the Windows Registry to the
	   correct filesystem.

       o   Any backslash ("\") characters in the path are replaced with forward slashes so that
	   libguestfs can process it.

       o   The path is resolved case insensitively to locate the file that should be edited.

       There are some known shortcomings:

       o   Some NTFS symbolic links may not be followed correctly.

       o   NTFS junction points that cross filesystems are not followed.

USING GUESTFISH
       guestfish(1) is a more powerful, lower level tool which you can use when "virt-edit"
       doesn't work.

       Using "virt-edit" is approximately equivalent to doing:

	guestfish --rw -i -d domname edit /file

       where "domname" is the name of the libvirt guest, and "/file" is the full path to the
       file.

       The command above uses libguestfs's guest inspection feature and so does not work on
       guests that libguestfs cannot inspect, or on things like arbitrary disk images that don't
       contain guests.	To edit a file on a disk image directly, use:

	guestfish --rw -a disk.img -m /dev/sda1 edit /file

       where "disk.img" is the disk image, "/dev/sda1" is the filesystem within the disk image to
       edit, and "/file" is the full path to the file.

       "virt-edit" cannot create new files.  Use the guestfish commands "touch", "write" or
       "upload" instead:

	guestfish --rw -i -d domname touch /newfile

	guestfish --rw -i -d domname write /newfile "new content"

	guestfish --rw -i -d domname upload localfile /newfile

ENVIRONMENT VARIABLES
       "EDITOR"
	   If set, this string is used as the editor.  It may contain arguments, eg. "emacs -nw"

	   If not set, "vi" is used.

SHELL QUOTING
       Libvirt guest names can contain arbitrary characters, some of which have meaning to the
       shell such as "#" and space.  You may need to quote or escape these characters on the
       command line.  See the shell manual page sh(1) for details.

EXIT STATUS
       This program returns 0 if successful, or non-zero if there was an error.

SEE ALSO
       guestfs(3), guestfish(1), virt-cat(1), virt-copy-in(1), virt-tar-in(1),
       http://libguestfs.org/, perl(1), perlre(1).

AUTHOR
       Richard W.M. Jones http://people.redhat.com/~rjones/

COPYRIGHT
       Copyright (C) 2009-2013 Red Hat Inc.

LICENSE
       This program is free software; you can redistribute it and/or modify it under the terms of
       the GNU General Public License as published by the Free Software Foundation; either
       version 2 of the License, or (at your option) any later version.

       This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
       without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
       See the GNU General Public License for more details.

       You should have received a copy of the GNU General Public License along with this program;
       if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
       Boston, MA 02110-1301 USA.

BUGS
       To get a list of bugs against libguestfs, use this link:
       https://bugzilla.redhat.com/buglist.cgi?component=libguestfs&product=Virtualization+Tools

       To report a new bug against libguestfs, use this link:
       https://bugzilla.redhat.com/enter_bug.cgi?component=libguestfs&product=Virtualization+Tools

       When reporting a bug, please supply:

       o   The version of libguestfs.

       o   Where you got libguestfs (eg. which Linux distro, compiled from source, etc)

       o   Describe the bug accurately and give a way to reproduce it.

       o   Run libguestfs-test-tool(1) and paste the complete, unedited output into the bug
	   report.

libguestfs-1.22.6			    2013-08-24				     virt-edit(1)
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