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I don't like this for the following reasons:
  • You are reading the whole file in memory TWICE! Once for the arguments to the foreach and another one when pushing everything into @data. In any case, you want to use while instead of foreach.
  • You are overwriting the file in place, without creating a backup. What if the machine crashes in the middle of the "print FILE @data"? You have lost your data.
I personally like the technique of writing the results to a new temporary file, and then renaming the original to a backup name and the temporary file to the original. Something like this:

open FILE, "/path/to/file" or die "$!\n"; open OUT, "/tmp/tmpfile.$$" or die "$!\n"; while(<FILE>) { next if /^\s*$/; print OUT, $_; } close FILE; close OUT; rename("/path/to/file", "/path/to/file.bak") or die "Error in rename: $!\n"; rename("/tmp/tmpfile.$$", "/path/to/file") or die "Error in rename: $!";
Side note: using "/tmp/tmpfile.$$" as a temporary file name could have security implications if the program is running set-uid. For better ways of creating a temporary file name, see the FAQ How do I make a temporary file name?

Also, a regex is not necessary if you are looking for strictly empty lines. But many times, a line is considered empty even if it contains white space, in this case using regular expressions is the best way to do it.

--ZZamboni


In reply to RE: Re: How do I remove blank lines from text files? by ZZamboni
in thread How do I remove blank lines from text files? by dumpest

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