Truncating just the superfluous newlines should work, too.  This would avoid rewriting the entire file, and/or reading it into memory. 

open my $fh, "+<", $fname or die $!;

my $pos = (-s $fh) - 1;
my $s;
do {
    seek $fh, $pos--, 0;
    read $fh, $s, 1;
} while $s eq "\n";

truncate $fh, $pos + 3;

[download]

(On Windows you'd need to truncate at $pos + 4, or else you'd have just a trailing \r, not a complete \r\n.)

Update: ww remarked via /msg that on Windows ActiveState Perl < 5.14, truncate only works on closed files (according to his tests), but that as of 5.14(.2) it does behave as expected.   I don't have Windows here to verify, so I can only pass this on as is.   Thanks anyway!

In reply to Re: How to remove newline characters at the end of file by Eliya
in thread How to remove newline characters at the end of file by ashokpj

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