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How do I pre-extend a file to a specified size

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Contributed by Anonymous Monk on Jan 03, 2001 at 22:16 UTC
Q&A  > files


Some operating systems can optimize file creation (especially for fixed binary record type files) if the file is pre-extended to desired size. This eliminates multiple file extension requests and can produce less fragmented files systems on multi-user systems.

Any tricks to indicate desired size of file during open?

Answer: How do I pre-extend a file to a specified size
contributed by merlyn

seek HANDLE, 0, $desired_size -1; print HANDLE "\0"; seek HANDLE, 0, 0;
contributed by abhishek_akj

open FILEHANDLE, " +< filename" or die "Unable to open: $! \n"; truncate FILEHANDLE, $desired_length or print "Unable to truncate: $ +! \n";
truncate just sets the filesize of the file opened by handle to whatever you specify; you can use it to remove characters from file as well as increase the filesize.


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