fallocate - preallocate space to a file.
fallocate [-n] [-o offset] -l length filename
fallocate is used to preallocate blocks to a file. For filesystems
which support the fallocate system call, this is done quickly by
allocating blocks and marking them as uninitialized, requiring no IO to
the data blocks. This is much faster than creating a file by filling
it with zeros.
As of the Linux Kernel v2.6.31, the fallocate system call is supported
by the btrfs, ext4, ocfs2, and xfs filesystems.
The exit code returned by fallocate is 0 on success and 1 on failure.
Print help and exit.
Do not modify the apparent length of the file. This may
effectively allocate blocks past EOF, which can be removed with
-o, --offset offset
Specifies the beginning offset of the allocation, in bytes.
Suffixes of k, m, g, t, p, e may be specified to denote KiB,
MiB, GiB, etc.
-l, --length length
Specifies the length of the allocation, in bytes. Suffixes of
k, m, g, t, p, e may be specified to denote KiB, MiB, GiB, etc.
Eric Sandeen <firstname.lastname@example.org>
Karel Zak <email@example.com>
fallocate(2), posix_fallocate(3), truncate(1)
The fallocate command is part of the util-linux-ng package and is
available from ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/.