1 =head2 add-cdrom | cdrom
5 This function adds a virtual CD-ROM disk image to the guest.
7 This is equivalent to the qemu parameter C<-cdrom filename>.
13 This function adds a virtual machine disk image C<filename> to the
14 guest. The first time you call this function, the disk appears as IDE
15 disk 0 (C</dev/sda>) in the guest, the second time as C</dev/sdb>, and
18 You don't necessarily need to be root when using libguestfs. However
19 you obviously do need sufficient permissions to access the filename
20 for whatever operations you want to perform (ie. read access if you
21 just want to read the image or write access if you want to modify the
24 This is equivalent to the qemu parameter C<-drive file=filename>.
30 Close the current Augeas handle and free up any resources
31 used by it. After calling this, you have to call
32 C<aug-init> again before you can use any other
37 aug-defnode name expr val
39 Defines a variable C<name> whose value is the result of
42 If C<expr> evaluates to an empty nodeset, a node is created,
43 equivalent to calling C<aug-set> C<expr>, C<value>.
44 C<name> will be the nodeset containing that single node.
46 On success this returns a pair containing the
47 number of nodes in the nodeset, and a boolean flag
48 if a node was created.
54 Defines an Augeas variable C<name> whose value is the result
55 of evaluating C<expr>. If C<expr> is NULL, then C<name> is
58 On success this returns the number of nodes in C<expr>, or
59 C<0> if C<expr> evaluates to something which is not a nodeset.
65 Look up the value associated with C<path>. If C<path>
66 matches exactly one node, the C<value> is returned.
72 Create a new Augeas handle for editing configuration files.
73 If there was any previous Augeas handle associated with this
74 guestfs session, then it is closed.
76 You must call this before using any other C<aug-*>
79 C<root> is the filesystem root. C<root> must not be NULL,
82 The flags are the same as the flags defined in
83 E<lt>augeas.hE<gt>, the logical I<or> of the following
88 =item C<AUG_SAVE_BACKUP> = 1
90 Keep the original file with a C<.augsave> extension.
92 =item C<AUG_SAVE_NEWFILE> = 2
94 Save changes into a file with extension C<.augnew>, and
95 do not overwrite original. Overrides C<AUG_SAVE_BACKUP>.
97 =item C<AUG_TYPE_CHECK> = 4
99 Typecheck lenses (can be expensive).
101 =item C<AUG_NO_STDINC> = 8
103 Do not use standard load path for modules.
105 =item C<AUG_SAVE_NOOP> = 16
107 Make save a no-op, just record what would have been changed.
109 =item C<AUG_NO_LOAD> = 32
111 Do not load the tree in C<aug-init>.
115 To close the handle, you can call C<aug-close>.
117 To find out more about Augeas, see L<http://augeas.net/>.
121 aug-insert path label true|false
123 Create a new sibling C<label> for C<path>, inserting it into
124 the tree before or after C<path> (depending on the boolean
127 C<path> must match exactly one existing node in the tree, and
128 C<label> must be a label, ie. not contain C</>, C<*> or end
129 with a bracketed index C<[N]>.
135 Load files into the tree.
137 See C<aug_load> in the Augeas documentation for the full gory
144 This is just a shortcut for listing C<aug-match>
145 C<path/*> and sorting the resulting nodes into alphabetical order.
151 Returns a list of paths which match the path expression C<path>.
152 The returned paths are sufficiently qualified so that they match
153 exactly one node in the current tree.
159 Move the node C<src> to C<dest>. C<src> must match exactly
160 one node. C<dest> is overwritten if it exists.
166 Remove C<path> and all of its children.
168 On success this returns the number of entries which were removed.
174 This writes all pending changes to disk.
176 The flags which were passed to C<aug-init> affect exactly
183 Set the value associated with C<path> to C<value>.
185 =head2 blockdev-flushbufs
187 blockdev-flushbufs device
189 This tells the kernel to flush internal buffers associated
192 This uses the L<blockdev(8)> command.
194 =head2 blockdev-getbsz
196 blockdev-getbsz device
198 This returns the block size of a device.
200 (Note this is different from both I<size in blocks> and
201 I<filesystem block size>).
203 This uses the L<blockdev(8)> command.
205 =head2 blockdev-getro
207 blockdev-getro device
209 Returns a boolean indicating if the block device is read-only
210 (true if read-only, false if not).
212 This uses the L<blockdev(8)> command.
214 =head2 blockdev-getsize64
216 blockdev-getsize64 device
218 This returns the size of the device in bytes.
220 See also C<blockdev-getsz>.
222 This uses the L<blockdev(8)> command.
224 =head2 blockdev-getss
226 blockdev-getss device
228 This returns the size of sectors on a block device.
229 Usually 512, but can be larger for modern devices.
231 (Note, this is not the size in sectors, use C<blockdev-getsz>
234 This uses the L<blockdev(8)> command.
236 =head2 blockdev-getsz
238 blockdev-getsz device
240 This returns the size of the device in units of 512-byte sectors
241 (even if the sectorsize isn't 512 bytes ... weird).
243 See also C<blockdev-getss> for the real sector size of
244 the device, and C<blockdev-getsize64> for the more
245 useful I<size in bytes>.
247 This uses the L<blockdev(8)> command.
249 =head2 blockdev-rereadpt
251 blockdev-rereadpt device
253 Reread the partition table on C<device>.
255 This uses the L<blockdev(8)> command.
257 =head2 blockdev-setbsz
259 blockdev-setbsz device blocksize
261 This sets the block size of a device.
263 (Note this is different from both I<size in blocks> and
264 I<filesystem block size>).
266 This uses the L<blockdev(8)> command.
268 =head2 blockdev-setro
270 blockdev-setro device
272 Sets the block device named C<device> to read-only.
274 This uses the L<blockdev(8)> command.
276 =head2 blockdev-setrw
278 blockdev-setrw device
280 Sets the block device named C<device> to read-write.
282 This uses the L<blockdev(8)> command.
288 Return the contents of the file named C<path>.
290 Note that this function cannot correctly handle binary files
291 (specifically, files containing C<\0> character which is treated
292 as end of string). For those you need to use the C<download>
293 function which has a more complex interface.
295 Because of the message protocol, there is a transfer limit
296 of somewhere between 2MB and 4MB. To transfer large files you should use
301 checksum csumtype path
303 This call computes the MD5, SHAx or CRC checksum of the
306 The type of checksum to compute is given by the C<csumtype>
307 parameter which must have one of the following values:
313 Compute the cyclic redundancy check (CRC) specified by POSIX
314 for the C<cksum> command.
318 Compute the MD5 hash (using the C<md5sum> program).
322 Compute the SHA1 hash (using the C<sha1sum> program).
326 Compute the SHA224 hash (using the C<sha224sum> program).
330 Compute the SHA256 hash (using the C<sha256sum> program).
334 Compute the SHA384 hash (using the C<sha384sum> program).
338 Compute the SHA512 hash (using the C<sha512sum> program).
342 The checksum is returned as a printable string.
348 Change the mode (permissions) of C<path> to C<mode>. Only
349 numeric modes are supported.
353 chown owner group path
355 Change the file owner to C<owner> and group to C<group>.
357 Only numeric uid and gid are supported. If you want to use
358 names, you will need to locate and parse the password file
359 yourself (Augeas support makes this relatively easy).
363 command 'arguments ...'
365 This call runs a command from the guest filesystem. The
366 filesystem must be mounted, and must contain a compatible
367 operating system (ie. something Linux, with the same
368 or compatible processor architecture).
370 The single parameter is an argv-style list of arguments.
371 The first element is the name of the program to run.
372 Subsequent elements are parameters. The list must be
373 non-empty (ie. must contain a program name).
375 The return value is anything printed to I<stdout> by
378 If the command returns a non-zero exit status, then
379 this function returns an error message. The error message
380 string is the content of I<stderr> from the command.
382 The C<$PATH> environment variable will contain at least
383 C</usr/bin> and C</bin>. If you require a program from
384 another location, you should provide the full path in the
387 Shared libraries and data files required by the program
388 must be available on filesystems which are mounted in the
389 correct places. It is the caller's responsibility to ensure
390 all filesystems that are needed are mounted at the right
393 Because of the message protocol, there is a transfer limit
394 of somewhere between 2MB and 4MB. To transfer large files you should use
399 command-lines 'arguments ...'
401 This is the same as C<command>, but splits the
402 result into a list of lines.
404 Because of the message protocol, there is a transfer limit
405 of somewhere between 2MB and 4MB. To transfer large files you should use
410 config qemuparam qemuvalue
412 This can be used to add arbitrary qemu command line parameters
413 of the form C<-param value>. Actually it's not quite arbitrary - we
414 prevent you from setting some parameters which would interfere with
415 parameters that we use.
417 The first character of C<param> string must be a C<-> (dash).
419 C<value> can be NULL.
425 This copies a file from C<src> to C<dest> where C<dest> is
426 either a destination filename or destination directory.
432 This copies a file or directory from C<src> to C<dest>
433 recursively using the C<cp -a> command.
437 debug subcmd 'extraargs ...'
439 The C<debug> command exposes some internals of
440 C<guestfsd> (the guestfs daemon) that runs inside the
443 There is no comprehensive help for this command. You have
444 to look at the file C<daemon/debug.c> in the libguestfs source
445 to find out what you can do.
451 This returns the kernel messages (C<dmesg> output) from
452 the guest kernel. This is sometimes useful for extended
453 debugging of problems.
455 Another way to get the same information is to enable
456 verbose messages with C<set-verbose> or by setting
457 the environment variable C<LIBGUESTFS_DEBUG=1> before
462 download remotefilename (filename|-)
464 Download file C<remotefilename> and save it as C<filename>
465 on the local machine.
467 C<filename> can also be a named pipe.
469 See also C<upload>, C<cat>.
471 Use C<-> instead of a filename to read/write from stdin/stdout.
475 drop-caches whattodrop
477 This instructs the guest kernel to drop its page cache,
478 and/or dentries and inode caches. The parameter C<whattodrop>
479 tells the kernel what precisely to drop, see
480 L<http://linux-mm.org/Drop_Caches>
482 Setting C<whattodrop> to 3 should drop everything.
484 This automatically calls L<sync(2)> before the operation,
485 so that the maximum guest memory is freed.
491 This compares the two files C<file1> and C<file2> and returns
492 true if their content is exactly equal, or false otherwise.
494 The external L<cmp(1)> program is used for the comparison.
500 This returns C<true> if and only if there is a file, directory
501 (or anything) with the given C<path> name.
503 See also C<is-file>, C<is-dir>, C<stat>.
509 This call uses the standard L<file(1)> command to determine
510 the type or contents of the file. This also works on devices,
511 for example to find out whether a partition contains a filesystem.
513 The exact command which runs is C<file -bsL path>. Note in
514 particular that the filename is not prepended to the output
521 This runs the filesystem checker (fsck) on C<device> which
522 should have filesystem type C<fstype>.
524 The returned integer is the status. See L<fsck(8)> for the
525 list of status codes from C<fsck>.
533 Multiple status codes can be summed together.
537 A non-zero return code can mean "success", for example if
538 errors have been corrected on the filesystem.
542 Checking or repairing NTFS volumes is not supported
547 This command is entirely equivalent to running C<fsck -a -t fstype device>.
553 Get the autosync flag.
559 This returns the ext2/3/4 filesystem label of the filesystem on
566 This returns the ext2/3/4 filesystem UUID of the filesystem on
573 Return the current search path.
575 This is always non-NULL. If it wasn't set already, then this will
576 return the default path.
582 Return the current qemu binary.
584 This is always non-NULL. If it wasn't set already, then this will
585 return the default qemu binary name.
591 This returns the current state as an opaque integer. This is
592 only useful for printing debug and internal error messages.
594 For more information on states, see L<guestfs(3)>.
600 This returns the verbose messages flag.
604 grub-install root device
606 This command installs GRUB (the Grand Unified Bootloader) on
607 C<device>, with the root directory being C<root>.
613 This runs C<hexdump -C> on the given C<path>. The result is
614 the human-readable, canonical hex dump of the file.
616 Because of the message protocol, there is a transfer limit
617 of somewhere between 2MB and 4MB. To transfer large files you should use
624 This returns true iff this handle is busy processing a command
625 (in the C<BUSY> state).
627 For more information on states, see L<guestfs(3)>.
633 This returns true iff this handle is being configured
634 (in the C<CONFIG> state).
636 For more information on states, see L<guestfs(3)>.
642 This returns C<true> if and only if there is a directory
643 with the given C<path> name. Note that it returns false for
644 other objects like files.
652 This returns C<true> if and only if there is a file
653 with the given C<path> name. Note that it returns false for
654 other objects like directories.
662 This returns true iff this handle is launching the subprocess
663 (in the C<LAUNCHING> state).
665 For more information on states, see L<guestfs(3)>.
671 This returns true iff this handle is ready to accept commands
672 (in the C<READY> state).
674 For more information on states, see L<guestfs(3)>.
676 =head2 kill-subprocess
680 This kills the qemu subprocess. You should never need to call this.
686 Internally libguestfs is implemented by running a virtual machine
689 You should call this after configuring the handle
690 (eg. adding drives) but before performing any actions.
696 List all the block devices.
698 The full block device names are returned, eg. C</dev/sda>
700 =head2 list-partitions
704 List all the partitions detected on all block devices.
706 The full partition device names are returned, eg. C</dev/sda1>
708 This does not return logical volumes. For that you will need to
715 List the files in C<directory> (relative to the root directory,
716 there is no cwd) in the format of 'ls -la'.
718 This command is mostly useful for interactive sessions. It
719 is I<not> intended that you try to parse the output string.
725 List the files in C<directory> (relative to the root directory,
726 there is no cwd). The '.' and '..' entries are not returned, but
727 hidden files are shown.
729 This command is mostly useful for interactive sessions. Programs
730 should probably use C<readdir> instead.
736 Returns file information for the given C<path>.
738 This is the same as C<stat> except that if C<path>
739 is a symbolic link, then the link is stat-ed, not the file it
742 This is the same as the C<lstat(2)> system call.
746 lvcreate logvol volgroup mbytes
748 This creates an LVM volume group called C<logvol>
749 on the volume group C<volgroup>, with C<size> megabytes.
751 =head2 lvm-remove-all
755 This command removes all LVM logical volumes, volume groups
756 and physical volumes.
758 B<This command is dangerous. Without careful use you
759 can easily destroy all your data>.
765 Remove an LVM logical volume C<device>, where C<device> is
766 the path to the LV, such as C</dev/VG/LV>.
768 You can also remove all LVs in a volume group by specifying
769 the VG name, C</dev/VG>.
775 List all the logical volumes detected. This is the equivalent
776 of the L<lvs(8)> command.
778 This returns a list of the logical volume device names
779 (eg. C</dev/VolGroup00/LogVol00>).
781 See also C<lvs-full>.
787 List all the logical volumes detected. This is the equivalent
788 of the L<lvs(8)> command. The "full" version includes all fields.
794 Create a directory named C<path>.
800 Create a directory named C<path>, creating any parent directories
801 as necessary. This is like the C<mkdir -p> shell command.
807 This creates a filesystem on C<device> (usually a partition
808 or LVM logical volume). The filesystem type is C<fstype>, for
813 mount device mountpoint
815 Mount a guest disk at a position in the filesystem. Block devices
816 are named C</dev/sda>, C</dev/sdb> and so on, as they were added to
817 the guest. If those block devices contain partitions, they will have
818 the usual names (eg. C</dev/sda1>). Also LVM C</dev/VG/LV>-style
821 The rules are the same as for L<mount(2)>: A filesystem must
822 first be mounted on C</> before others can be mounted. Other
823 filesystems can only be mounted on directories which already
826 The mounted filesystem is writable, if we have sufficient permissions
827 on the underlying device.
829 The filesystem options C<sync> and C<noatime> are set with this
830 call, in order to improve reliability.
834 mount-options options device mountpoint
836 This is the same as the C<mount> command, but it
837 allows you to set the mount options as for the
838 L<mount(8)> I<-o> flag.
842 mount-ro device mountpoint
844 This is the same as the C<mount> command, but it
845 mounts the filesystem with the read-only (I<-o ro>) flag.
849 mount-vfs options vfstype device mountpoint
851 This is the same as the C<mount> command, but it
852 allows you to set both the mount options and the vfstype
853 as for the L<mount(8)> I<-o> and I<-t> flags.
859 This returns the list of currently mounted filesystems. It returns
860 the list of devices (eg. C</dev/sda1>, C</dev/VG/LV>).
862 Some internal mounts are not shown.
868 This moves a file from C<src> to C<dest> where C<dest> is
869 either a destination filename or destination directory.
875 This is a test probe into the guestfs daemon running inside
876 the qemu subprocess. Calling this function checks that the
877 daemon responds to the ping message, without affecting the daemon
878 or attached block device(s) in any other way.
884 This creates an LVM physical volume on the named C<device>,
885 where C<device> should usually be a partition name such
892 This wipes a physical volume C<device> so that LVM will no longer
895 The implementation uses the C<pvremove> command which refuses to
896 wipe physical volumes that contain any volume groups, so you have
897 to remove those first.
903 List all the physical volumes detected. This is the equivalent
904 of the L<pvs(8)> command.
906 This returns a list of just the device names that contain
907 PVs (eg. C</dev/sda2>).
909 See also C<pvs-full>.
915 List all the physical volumes detected. This is the equivalent
916 of the L<pvs(8)> command. The "full" version includes all fields.
922 Return the contents of the file named C<path>.
924 The file contents are returned as a list of lines. Trailing
925 C<LF> and C<CRLF> character sequences are I<not> returned.
927 Note that this function cannot correctly handle binary files
928 (specifically, files containing C<\0> character which is treated
929 as end of line). For those you need to use the C<read-file>
930 function which has a more complex interface.
936 Remove the single file C<path>.
942 Remove the file or directory C<path>, recursively removing the
943 contents if its a directory. This is like the C<rm -rf> shell
950 Remove the single directory C<path>.
952 =head2 set-autosync | autosync
954 set-autosync true|false
956 If C<autosync> is true, this enables autosync. Libguestfs will make a
957 best effort attempt to run C<umount-all> followed by
958 C<sync> when the handle is closed
959 (also if the program exits without closing handles).
961 This is disabled by default (except in guestfish where it is
966 set-e2label device label
968 This sets the ext2/3/4 filesystem label of the filesystem on
969 C<device> to C<label>. Filesystem labels are limited to
972 You can use either C<tune2fs-l> or C<get-e2label>
973 to return the existing label on a filesystem.
977 set-e2uuid device uuid
979 This sets the ext2/3/4 filesystem UUID of the filesystem on
980 C<device> to C<uuid>. The format of the UUID and alternatives
981 such as C<clear>, C<random> and C<time> are described in the
982 L<tune2fs(8)> manpage.
984 You can use either C<tune2fs-l> or C<get-e2uuid>
985 to return the existing UUID of a filesystem.
987 =head2 set-path | path
991 Set the path that libguestfs searches for kernel and initrd.img.
993 The default is C<$libdir/guestfs> unless overridden by setting
994 C<LIBGUESTFS_PATH> environment variable.
996 The string C<path> is stashed in the libguestfs handle, so the caller
997 must make sure it remains valid for the lifetime of the handle.
999 Setting C<path> to C<NULL> restores the default path.
1001 =head2 set-qemu | qemu
1005 Set the qemu binary that we will use.
1007 The default is chosen when the library was compiled by the
1010 You can also override this by setting the C<LIBGUESTFS_QEMU>
1011 environment variable.
1013 The string C<qemu> is stashed in the libguestfs handle, so the caller
1014 must make sure it remains valid for the lifetime of the handle.
1016 Setting C<qemu> to C<NULL> restores the default qemu binary.
1018 =head2 set-verbose | verbose
1020 set-verbose true|false
1022 If C<verbose> is true, this turns on verbose messages (to C<stderr>).
1024 Verbose messages are disabled unless the environment variable
1025 C<LIBGUESTFS_DEBUG> is defined and set to C<1>.
1029 sfdisk device cyls heads sectors 'lines ...'
1031 This is a direct interface to the L<sfdisk(8)> program for creating
1032 partitions on block devices.
1034 C<device> should be a block device, for example C</dev/sda>.
1036 C<cyls>, C<heads> and C<sectors> are the number of cylinders, heads
1037 and sectors on the device, which are passed directly to sfdisk as
1038 the I<-C>, I<-H> and I<-S> parameters. If you pass C<0> for any
1039 of these, then the corresponding parameter is omitted. Usually for
1040 'large' disks, you can just pass C<0> for these, but for small
1041 (floppy-sized) disks, sfdisk (or rather, the kernel) cannot work
1042 out the right geometry and you will need to tell it.
1044 C<lines> is a list of lines that we feed to C<sfdisk>. For more
1045 information refer to the L<sfdisk(8)> manpage.
1047 To create a single partition occupying the whole disk, you would
1048 pass C<lines> as a single element list, when the single element being
1049 the string C<,> (comma).
1051 B<This command is dangerous. Without careful use you
1052 can easily destroy all your data>.
1058 Returns file information for the given C<path>.
1060 This is the same as the C<stat(2)> system call.
1066 Returns file system statistics for any mounted file system.
1067 C<path> should be a file or directory in the mounted file system
1068 (typically it is the mount point itself, but it doesn't need to be).
1070 This is the same as the C<statvfs(2)> system call.
1076 This runs the L<strings(1)> command on a file and returns
1077 the list of printable strings found.
1079 Because of the message protocol, there is a transfer limit
1080 of somewhere between 2MB and 4MB. To transfer large files you should use
1085 strings-e encoding path
1087 This is like the C<strings> command, but allows you to
1088 specify the encoding.
1090 See the L<strings(1)> manpage for the full list of encodings.
1092 Commonly useful encodings are C<l> (lower case L) which will
1093 show strings inside Windows/x86 files.
1095 The returned strings are transcoded to UTF-8.
1097 Because of the message protocol, there is a transfer limit
1098 of somewhere between 2MB and 4MB. To transfer large files you should use
1105 This syncs the disk, so that any writes are flushed through to the
1106 underlying disk image.
1108 You should always call this if you have modified a disk image, before
1113 tar-in (tarfile|-) directory
1115 This command uploads and unpacks local file C<tarfile> (an
1116 I<uncompressed> tar file) into C<directory>.
1118 To upload a compressed tarball, use C<tgz-in>.
1120 Use C<-> instead of a filename to read/write from stdin/stdout.
1124 tar-out directory (tarfile|-)
1126 This command packs the contents of C<directory> and downloads
1127 it to local file C<tarfile>.
1129 To download a compressed tarball, use C<tgz-out>.
1131 Use C<-> instead of a filename to read/write from stdin/stdout.
1135 tgz-in (tarball|-) directory
1137 This command uploads and unpacks local file C<tarball> (a
1138 I<gzip compressed> tar file) into C<directory>.
1140 To upload an uncompressed tarball, use C<tar-in>.
1142 Use C<-> instead of a filename to read/write from stdin/stdout.
1146 tgz-out directory (tarball|-)
1148 This command packs the contents of C<directory> and downloads
1149 it to local file C<tarball>.
1151 To download an uncompressed tarball, use C<tar-out>.
1153 Use C<-> instead of a filename to read/write from stdin/stdout.
1159 Touch acts like the L<touch(1)> command. It can be used to
1160 update the timestamps on a file, or, if the file does not exist,
1161 to create a new zero-length file.
1167 This returns the contents of the ext2, ext3 or ext4 filesystem
1168 superblock on C<device>.
1170 It is the same as running C<tune2fs -l device>. See L<tune2fs(8)>
1171 manpage for more details. The list of fields returned isn't
1172 clearly defined, and depends on both the version of C<tune2fs>
1173 that libguestfs was built against, and the filesystem itself.
1175 =head2 umount | unmount
1179 This unmounts the given filesystem. The filesystem may be
1180 specified either by its mountpoint (path) or the device which
1181 contains the filesystem.
1183 =head2 umount-all | unmount-all
1187 This unmounts all mounted filesystems.
1189 Some internal mounts are not unmounted by this call.
1193 upload (filename|-) remotefilename
1195 Upload local file C<filename> to C<remotefilename> on the
1198 C<filename> can also be a named pipe.
1200 See also C<download>.
1202 Use C<-> instead of a filename to read/write from stdin/stdout.
1206 vgcreate volgroup 'physvols ...'
1208 This creates an LVM volume group called C<volgroup>
1209 from the non-empty list of physical volumes C<physvols>.
1215 Remove an LVM volume group C<vgname>, (for example C<VG>).
1217 This also forcibly removes all logical volumes in the volume
1224 List all the volumes groups detected. This is the equivalent
1225 of the L<vgs(8)> command.
1227 This returns a list of just the volume group names that were
1228 detected (eg. C<VolGroup00>).
1230 See also C<vgs-full>.
1236 List all the volumes groups detected. This is the equivalent
1237 of the L<vgs(8)> command. The "full" version includes all fields.
1241 write-file path content size
1243 This call creates a file called C<path>. The contents of the
1244 file is the string C<content> (which can contain any 8 bit data),
1245 with length C<size>.
1247 As a special case, if C<size> is C<0>
1248 then the length is calculated using C<strlen> (so in this case
1249 the content cannot contain embedded ASCII NULs).
1251 I<NB.> Owing to a bug, writing content containing ASCII NUL
1252 characters does I<not> work, even if the length is specified.
1253 We hope to resolve this bug in a future version. In the meantime
1256 Because of the message protocol, there is a transfer limit
1257 of somewhere between 2MB and 4MB. To transfer large files you should use
1264 This command writes zeroes over the first few blocks of C<device>.
1266 How many blocks are zeroed isn't specified (but it's I<not> enough
1267 to securely wipe the device). It should be sufficient to remove
1268 any partition tables, filesystem superblocks and so on.