Fix UPDATES and host_cpu in configure.ac.

[libguestfs.git] / guestfish.pod

=encoding utf8

=head1 NAME

guestfish - the libguestfs filesystem interactive shell

=head1 SYNOPSIS

 guestfish [--options] [commands]

 guestfish -i libvirt-domain

 guestfish -i disk-image(s)

=head1 EXAMPLES

=head2 From shell scripts

Create a new C</etc/motd> file in a guest:

 guestfish <<_EOF_
 add disk.img
 run
 mount /dev/VolGroup00/LogVol00 /
 write_file /etc/motd "Hello users" 0
 _EOF_

List the LVs in a guest:

 guestfish <<_EOF_
 add disk.img
 run
 lvs
 _EOF_

=head2 On the command line

List the LVM PVs in a guest image:

 guestfish add disk.img : run : pvs

Remove C</boot/grub/menu.lst> (in reality not such a great idea):

 guestfish --add disk.img \
   --mount /dev/VolGroup00/LogVol00 \
   --mount /dev/sda1:/boot \
   rm /boot/grub/menu.lst

=head2 As an interactive shell

 $ guestfish

 Welcome to guestfish, the libguestfs filesystem interactive shell for
 editing virtual machine filesystems.

 Type: 'help' for help with commands
       'quit' to quit the shell

 ><fs> help

=head2 As a script interpreter

 #!/usr/bin/guestfish -f
 alloc /tmp/output.img 10M
 run
 sfdisk /dev/sda 0 0 0 ,
 mkfs ext2 /dev/sda1

=head1 DESCRIPTION

Guestfish is a shell and command-line tool for examining and modifying
virtual machine filesystems.  It uses libguestfs and exposes all of
the functionality of the guestfs API, see L<guestfs(3)>.

=head1 OPTIONS

=over 4

=item B<--help>

Displays general help on options.

=item B<-h> | B<--cmd-help>

Lists all available guestfish commands.

=item B<-h cmd> | B<--cmd-help cmd>

Displays detailed help on a single command C<cmd>.

=item B<-a image> | B<--add image>

Add a block device or virtual machine image to the shell.

=item B<-f file> | B<--file file>

Read commands from C<file>.  To write pure guestfish
scripts, use:

 #!/usr/bin/guestfish -f

=item B<-i> | B<--inspector>

Run virt-inspector on the named libvirt domain or list of disk
images.  If virt-inspector is available and if it can identify
the domain or disk images, then partitions will be mounted
correctly at start-up.

Typical usage is either:

 guestfish -i myguest

(for an inactive libvirt domain called I<myguest>), or:

 guestfish --ro -i myguest

(for active domains, readonly), or specify the block device directly:

 guestfish -i /dev/Guests/MyGuest

You cannot use I<-a> or I<-m> in conjunction with this option, and
options other than I<--ro> might not behave correctly.

See also: L<virt-inspector(1)>.

=item B<-m dev[:mountpoint]> | B<--mount dev[:mountpoint]>

Mount the named partition or logical volume on the given mountpoint.

If the mountpoint is omitted, it defaults to C</>.

You have to mount something on C</> before most commands will work.

If any C<-m> or C<--mount> options are given, the guest is
automatically launched.

=item B<-n> | B<--no-sync>

Disable autosync.  This is enabled by default.  See the discussion
of autosync in the L<guestfs(3)> manpage.

=item B<-r> | B<--ro>

This changes the C<-m> option so that mounts are done read-only
(see C<guestfs_mount_ro> in the L<guestfs(3)> manpage).

=item B<-v> | B<--verbose>

Enable very verbose messages.  This is particularly useful if you find
a bug.

=item B<-D> | B<--no-dest-paths>

Don't tab-complete paths on the guest filesystem.  It is useful to be
able to hit the tab key to complete paths on the guest filesystem, but
this causes extra "hidden" guestfs calls to be made, so this option is
here to allow this feature to be disabled.

=item B<-V> | B<--version>

Display the guestfish / libguestfs version number and exit.

=back

=head1 COMMANDS ON COMMAND LINE

Any additional (non-option) arguments are treated as commands to
execute.

Commands to execute should be separated by a colon (C<:>), where the
colon is a separate parameter.  Thus:

 guestfish cmd [args...] : cmd [args...] : cmd [args...] ...

If there are no additional arguments, then we enter a shell, either an
interactive shell with a prompt (if the input is a terminal) or a
non-interactive shell.

In either command line mode or non-interactive shell, the first
command that gives an error causes the whole shell to exit.  In
interactive mode (with a prompt) if a command fails, you can continue
to enter commands.

=head1 USING launch (OR run)

As with L<guestfs(3)>, you must first configure your guest by adding
disks, then launch it, then mount any disks you need, and finally
issue actions/commands.  So the general order of the day is:

=over 4

=item *

add or -a/--add

=item *

launch (aka run)

=item *

mount or -m/--mount

=item *

any other commands

=back

C<run> is a synonym for C<launch>.  You must C<launch> (or C<run>)
your guest before mounting or performing any other commands.

The only exception is that if the C<-m> or C<--mount> option was
given, the guest is automatically run for you (simply because
guestfish can't mount the disks you asked for without doing this).

=head1 QUOTING

You can quote ordinary parameters using either single or double
quotes.  For example:

 add "file with a space.img"

 rm '/file name'

 rm '/"'

A few commands require a list of strings to be passed.  For these, use
a space-separated list, enclosed in quotes.  For example:

 vgcreate VG "/dev/sda1 /dev/sdb1"

=head1 WILDCARDS AND GLOBBING

Neither guestfish nor the underlying guestfs API performs
wildcard expansion (globbing) by default.  So for example the
following will not do what you expect:

 rm-rf /home/*

Assuming you don't have a directory literally called C</home/*>
then the above command will return an error.

To perform wildcard expansion, use the C<glob> command.

 glob rm-rf /home/*

runs C<rm-rf> on each path that matches (ie. potentially running
the command many times), equivalent to:

 rm-rf /home/jim
 rm-rf /home/joe
 rm-rf /home/mary

C<glob> only works on simple guest paths and not on device names.

If you have several parameters, each containing a wildcard, then glob
will perform a cartesian product.

=head1 COMMENTS

Any line which starts with a I<#> character is treated as a comment
and ignored.  The I<#> can optionally be preceeded by whitespace,
but B<not> by a command.  For example:

 # this is a comment
         # this is a comment
 foo # NOT a comment

Blank lines are also ignored.

=head1 RUNNING COMMANDS LOCALLY

Any line which starts with a I<!> character is treated as a command
sent to the local shell (C</bin/sh> or whatever L<system(3)> uses).
For example:

 !mkdir local
 tgz-out /remote local/remote-data.tar.gz

will create a directory C<local> on the host, and then export
the contents of C</remote> on the mounted filesystem to
C<local/remote-data.tar.gz>.  (See C<tgz-out>).

=head1 PIPES

Use C<command E<lt>spaceE<gt> | command> to pipe the output of the
first command (a guestfish command) to the second command (any host
command).  For example:

 cat /etc/passwd | awk -F: '$3 == 0 { print }'

(where C<cat> is the guestfish cat command, but C<awk> is the host awk
program).  The above command would list all accounts in the guest
filesystem which have UID 0, ie. root accounts including backdoors.
Other examples:

 hexdump /bin/ls | head
 list-devices | tail -1

The space before the pipe symbol is required, any space after the pipe
symbol is optional.  Everything after the pipe symbol is just passed
straight to the host shell, so it can contain redirections, globs and
anything else that makes sense on the host side.

To use a literal argument which begins with a pipe symbol, you have
to quote it, eg:

 echo "|"

=head1 EXIT ON ERROR BEHAVIOUR

By default, guestfish will ignore any errors when in interactive mode
(ie. taking commands from a human over a tty), and will exit on the
first error in non-interactive mode (scripts, commands given on the
command line).

If you prefix a command with a I<-> character, then that command will
not cause guestfish to exit, even if that (one) command returns an
error.

=head1 GUESTFISH COMMANDS

The commands in this section are guestfish convenience commands, in
other words, they are not part of the L<guestfs(3)> API.

=head2 alloc | allocate

 alloc filename size

This creates an empty (zeroed) file of the given size, and then adds
so it can be further examined.

For more advanced image creation, see L<qemu-img(1)> utility.

Size can be specified (where C<nn> means a number):

=over 4

=item C<nn> or C<nn>K or C<nn>KB

number of kilobytes, eg: C<1440> = standard 3.5in floppy

=item C<nn>M or C<nn>MB

number of megabytes

=item C<nn>G or C<nn>GB

number of gigabytes

=item C<nn>sects

number of 512 byte sectors

=back

=head2 echo

 echo [params ...]

This echos the parameters to the terminal.

=head2 edit | vi | emacs

 edit filename

This is used to edit a file.  It downloads the file, edits it
locally using your editor, then uploads the result.

The editor is C<$EDITOR>.  However if you use the alternate
commands C<vi> or C<emacs> you will get those corresponding
editors.

NOTE: This will not work reliably for large files
(> 2 MB) or binary files containing \0 bytes.

=head2 glob

 glob command args...

Expand wildcards in any paths in the args list, and run C<command>
repeatedly on each matching path.

See section WILDCARDS AND GLOBBING.

=head2 help

 help
 help cmd

Without any parameter, this lists all commands.  With a C<cmd>
parameter, this displays detailed help for a command.

=head2 lcd

 lcd directory

Change the local directory, ie. the current directory of guestfish
itself.

Note that C<!cd> won't do what you might expect.

=head2 more | less

 more filename

 less filename

This is used to view a file.

The default viewer is C<$PAGER>.  However if you use the alternate
command C<less> you will get the C<less> command specifically.

NOTE: This will not work reliably for large files
(> 2 MB) or binary files containing \0 bytes.

=head2 quit | exit

This exits guestfish.  You can also use C<^D> key.

=head2 time

 time command args...

Run the command as usual, but print the elapsed time afterwards.  This
can be useful for benchmarking operations.

=head1 COMMANDS

@ACTIONS@

=head1 ENVIRONMENT VARIABLES

=over 4

=item EDITOR

The C<edit> command uses C<$EDITOR> as the editor.  If not
set, it uses C<vi>.

=item HOME

If compiled with GNU readline support, then the command history
is saved in C<$HOME/.guestfish>

=item LIBGUESTFS_APPEND

Pass additional options to the guest kernel.

=item LIBGUESTFS_DEBUG

Set C<LIBGUESTFS_DEBUG=1> to enable verbose messages.  This has the
same effect as using the B<-v> option.

=item LIBGUESTFS_MEMSIZE

Set the memory allocated to the qemu process, in megabytes.  For
example:

 LIBGUESTFS_MEMSIZE=700

=item LIBGUESTFS_PATH

Set the path that guestfish uses to search for kernel and initrd.img.
See the discussion of paths in L<guestfs(3)>.

=item LIBGUESTFS_QEMU

Set the default qemu binary that libguestfs uses.  If not set, then
the qemu which was found at compile time by the configure script is
used.

=item PAGER

The C<more> command uses C<$PAGER> as the pager.  If not
set, it uses C<more>.

=back

=head1 EXIT CODE

guestfish returns I<0> if the commands completed without error, or
I<1> if there was an error.

=head1 SEE ALSO

L<guestfs(3)>,
L<http://libguestfs.org/>.

=head1 AUTHORS

Richard W.M. Jones (C<rjones at redhat dot com>)

=head1 COPYRIGHT

Copyright (C) 2009 Red Hat Inc.
L<http://libguestfs.org/>

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., 675 Mass Ave, Cambridge, MA 02139, USA.