1FALLOCATE(1)                General Commands Manual               FALLOCATE(1)
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NAME

6       fallocate - preallocate space to a file.
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SYNOPSIS

9       fallocate [-n] [-p] [-o offset] -l length filename
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DESCRIPTION

12       fallocate  is  used  to  preallocate blocks to a file.  For filesystems
13       which support the fallocate system call, this is done quickly by  allo‐
14       cating blocks and marking them as uninitialized, requiring no IO to the
15       data blocks.  This is much faster than creating a file  by  filling  it
16       with zeros.
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18       As  of the Linux Kernel v2.6.31, the fallocate system call is supported
19       by the btrfs, ext4, ocfs2, and xfs filesystems.
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21       The exit code returned by fallocate is 0 on success and 1 on failure.
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OPTIONS

24       -h, --help
25              Print help and exit.
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27       -n, --keep-size
28              Do not modify the apparent length of the file. This  may  effec‐
29              tively  allocate  blocks  past  EOF, which can be removed with a
30              truncate.
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32       -p, --punch-hole
33              Punch holes in the file, the range should not exceed the  length
34              of the file.
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36       -o, --offset offset
37              Specifies  the  beginning  offset  of  the allocation, in bytes.
38              Suffixes of k, m, g, t, p, e may be  specified  to  denote  KiB,
39              MiB, GiB, etc.
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41       -l, --length length
42              Specifies  the  length of the allocation, in bytes.  Suffixes of
43              k, m, g, t, p, e may be specified to denote KiB, MiB, GiB, etc.
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AUTHORS

46       Eric Sandeen <sandeen@redhat.com>
47       Karel Zak <kzak@redhat.com>
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SEE ALSO

50       fallocate(2), posix_fallocate(3), truncate(1)
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AVAILABILITY

53       The fallocate command is part  of  the  util-linux-ng  package  and  is
54       available from ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/.
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59Version 1.0                        Jul 2009                       FALLOCATE(1)