prealloc.1 (2010 09)

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prealloc(1) prealloc(1)
NAME
prealloc - preallocate disk storage
SYNOPSIS
prealloc name size
DESCRIPTION
prealloc preallocates at least size bytes of disk space for an ordinary file name , creating the file if
name does not already exist. The space is allocated in an implementation-dependent fashion for fast
sequential reads and writes of the file.
prealloc fails and no disk space is allocated if name already exists and is not an ordinary file of zero
length, if insufficient space is left on disk, or if size exceeds the maximum file size or the file size limit of
the process (see ulimit (2)). The file is zero-filled.
DIAGNOSTICS
prealloc returns one of the following values upon completion:
0 Successful completion.
1 name already exists and is not an ordinary file of zero length.
2 There is insufficient room on the disk.
3 size exceeds file size limits.
EXAMPLES
The following example preallocates 50 000 bytes for the file myfile:
prealloc myfile 50000
WARNINGS
Allocation of file space is highly dependent on current disk usage. A successful return does not indicate
how fragmented the file actually might be if the disk is approaching its capacity.
AUTHOR
prealloc was developed by HP.
SEE ALSO
prealloc(2), ulimit(2).
HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1