What’s the difference between iterating over a file with foreach or while in Perl?

vinoth.ree has asked for the wisdom of the Perl Monks concerning the following question:

I got this question from this site

They would have given some answers, but I did not get the clarification, thats why I posted this question here to get more clarification I am sorry that I not informed the site where I got this question pardon me! please

I have a filehandle FILE in Perl, and I want to iterate over all the lines in the file. Is there a difference between the following?

while (<FILE>) {
    # do something
}

and

foreach (<FILE>) {
    # do something
}
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Vinoth,G

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Re: What’s the difference between iterating over a file with foreach or while in Perl? by almut (Canon) on Apr 20, 2009 at 10:10 UTC
Is there a difference ...? Yes, the `foreach` will read the entire file into memory before it starts to `'# do something'`, while the `while` will process the file line by line (unless you've changed the default input record separator `$/`). In the `foreach` case, the `<FILE>` is evaluated in list context, in the `while` case in scalar context.	[reply] [d/l] [select]
Re: What’s the difference between iterating over a file with foreach or while in Perl? by Corion (Patriarch) on Apr 20, 2009 at 13:18 UTC
See What’s the difference between iterating over a file with foreach or while in Perl? on stackoverflow.com.	[reply]
Re: What’s the difference between iterating over a file with foreach or while in Perl? by Anonymous Monk on Apr 20, 2009 at 10:25 UTC
readline in scalar context (while) returns one line, but in list context (foreach) returns all lines	[reply]

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