1nbdsh(1) LIBNBD nbdsh(1)
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6 nbdsh - network block device (NBD) shell
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9 $ nbdsh
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11 Welcome to nbdsh, the shell for interacting with
12 Network Block Device (NBD) servers.
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14 The ‘nbd’ module has already been imported and there
15 is an open NBD handle called ‘h’.
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17 nbd> h.connect_command (["nbdkit", "-s", "memory", "1G"])
18 nbd> h.get_size ()
19 1073741824
20 nbd> buf = b"hello, world"
21 nbd> h.pwrite (buf, 0, 0)
22 nbd> exit()
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25 nbdsh is a Python-based client shell for accessing Network Block Device
26 (NBD) servers.
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28 For documentation about the libnbd API please open the shell and type:
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30 help (nbd)
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33 Print the size of an NBD export
34 The -u option connects to an NBD URI. The -c option lets you execute
35 single Python statements from the command line. Combining these two
36 options lets you print the size in bytes of an NBD export:
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38 $ nbdsh -u nbd://localhost -c 'print (h.get_size ())'
39 1073741824
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41 Hexdump the boot sector of an NBD export
42 Using -c - you can feed a whole Python program to the standard input of
43 nbdsh:
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45 nbdsh -c - <<'EOF'
46 from subprocess import *
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48 h.connect_uri ("nbd://localhost")
49 bootsect = h.pread (512, 0)
50 p = Popen ("hexdump -C", shell=True, stdin=PIPE)
51 p.stdin.write (bootsect)
52 EOF
53
55 -h
56 --help
57 Display brief command line help and exit.
58
59 --base-allocation
60 Request the use of the "base:allocation" meta context, which is the
61 most common context used with nbd_block_status(3). This is
62 equivalent to calling
63 "h.set_meta_context (nbd.CONTEXT_BASE_ALLOCATION)" in the shell
64 prior to connecting.
65
66 -c 'COMMAND ...'
67 --command 'COMMAND ...'
68 Instead of starting an interactive shell, run a command. This
69 option can be specified multiple times in order to run multiple
70 commands.
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72 -c -
73 --command -
74 Read standard input and execute it as a command.
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76 -u URI
77 -uri URI
78 --connect URI
79 Connect to the given NBD URI. This is equivalent to the
80 "h.connect_uri (URI)" command in the shell.
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82 -V
83 --version
84 Display the package name and version and exit.
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87 libnbd(3), libnbd-security(3), nbdfuse(1), qemu-img(1).
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90 Richard W.M. Jones
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93 Copyright (C) 2019 Red Hat Inc.
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96 This library is free software; you can redistribute it and/or modify it
97 under the terms of the GNU Lesser General Public License as published
98 by the Free Software Foundation; either version 2 of the License, or
99 (at your option) any later version.
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101 This library is distributed in the hope that it will be useful, but
102 WITHOUT ANY WARRANTY; without even the implied warranty of
103 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
104 Lesser General Public License for more details.
105
106 You should have received a copy of the GNU Lesser General Public
107 License along with this library; if not, write to the Free Software
108 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
109 02110-1301 USA
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113libnbd-1.3.7 2020-04-23 nbdsh(1)