On Thu, 02 Jan 2014 11:18:31 -0500
Uri Guttman <u...@stemsystems.com> wrote:
> On 01/02/2014 10:39 AM, David Precious wrote:
> > Secondly - do you need to work on the file as a whole, or can you
> > just loop over it, making changes, and writing them back out? In
> > other words, do you *need* to hold the whole file in memory at one
> > time? More often than not, you don't.
> >
> > If it's per-line changes, then File::Slurp::edit_file_lines should
> > work
> > - for e.g.:
> >
> > use File::Slurp qw(edit_file_lines);
> > my $filename = '/tmp/foo';
> > edit_file_lines(sub { s/badger/mushroom/g }, $filename);
> >
> > The above would of course replace every occurrence of 'badger' with
> > 'mushroom' in the file.
>
> if there is a size issue, that would be just as bad as slurping in
> the whole file and it would use even more storage as it will be an
> array of all the lines internally.
Oh - my mistake, I'd believed that edit_file_lines edited the file
line-by-line, writing the results to a temporary file and then
renaming the temporary file over the original at the end.
In that case, I think the docs are a little unclear:
"These subs read in a file into $_, execute a code block which should
modify $_ and then write $_ back to the file. The difference between
them is that edit_file reads the whole file into $_ and calls the code
block one time. With edit_file_lines each line is read into $_ and the
code is called for each line..."
and
"These subs are the equivalent of the -pi command line options of
Perl..."
... to me, that sounds like edit_file_lines reads a line at a time
rather than slurping the whole lot - but looking at the code, it does
indeed read the entire file contents into RAM. (I probably should have
expected anything in File::Slurp to, well, slurp the file... :) )
Part of me wonders if File::Slurp should provide an in-place (not
slurping into RAM) editing feature which works like edit_file_lines but
line-by-line using a temp file, but that's probably feature creep :)
OP - what didn't work about Tie::File?
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David Precious ("bigpresh") <dav...@preshweb.co.uk>
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