http://qs1969.pair.com?node_id=2871
Description: I think that both of these use the minimum amount of code. (doing the job properly - using my and close)
Post if you have a better way!
Return the file contents as a scalar value 
sub readfile {
    my $OP ;
    open FS, $_[0] ;
    while (<FS>) {$OP .= $_}
    close FS ;
    return $OP ;
}


Returns the contents of a file in list form (line by line) 
sub readlines {
    open FS, $_[0] ;
    my (@OP) = <FS> ;
    close FS ;
    return (@OP) ;
}
Replies are listed 'Best First'.
RE: Return the contents of a file
by btrott (Parson) on Feb 04, 2000 at 23:31 UTC
    Two things:

    1) that while loop should read: 

       while (<FS>) { $OP .= $_ }

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    Note the all-important ".=" instead of "=" (probably just a mistype on your part. :)

    2) your opens should always check for error messages, and you should get faster results slurping the whole file in as one string, like so: 

        sub readfile {
        my $OP;
        open FS, $_[0] or die "Can't open $_[0]: $!";
        {
            local $/ = undef;
            $OP = <FS>;
        }
        close FS or die "Can't close $_[0]: $!";
        return $OP;
    }

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      Here's another version: 

      sub readfile {
  local $/="" unless wantarray;
  return open(FS, shift) ? <FS> : undef;
}

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      No 'my' variables, handles both string and array requests, and returns undef if the file could not be opened. Use it like this:

      defined($slurp = &readfile($file)) or die "Could not open $file: $!\n"
+;
print "Scalar 'slurp' now has ", length $slurp, " characters in it\n";
defined(@slurp = &readfile($file)) or die "Could not open $file: $!\n"
+;
print "Array 'slurp' now has ", $#slurp, " elements in it.\n";

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        WOW!
        Just loves to see this.
        -anders
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      I REALLY do like this one. I've found that it works great for small files. Has anyone had any experiences using this technique w/ something large like a *.cvs file from a database dump? Are there any memory issues to handling a variable that large. -- I shouldn't thinks so. Hmmm...
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        There *are* memory issues in having very large variables, just as there would be, presumably, in any language. Perl variables take up a lot of space. From perlfaq3: 
            When it comes to time-space tradeoffs, Perl nearly
    always prefers to throw memory at a problem. Scalars
    in Perl use more memory than strings in C, arrays
    take more that, and hashes use even more.

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        I mean, if you *can* process a file line by line, it's best to do so.
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RE: Return the contents of a file
by chromatic (Archbishop) on Apr 12, 2000 at 18:43 UTC
    You can also redefine the input record separator $/ to a null string: 
    local $/;
my $scalar = <FH>;

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    That obviates the need for a while loop. Normally, $/ is set to a newline. That's why the magic <FILEHANDLE> reads one line at a time. Using a local $/ will change that to whatever separator you want. Specify none, slurp the whole thing. That could make your first example even more compact.
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