in reply to Re: Re: Re: Extract lines and output...
in thread Extract lines and output...

I like it really brief. The only reason I have close(I)
is to reset $. You don't ever use $. so $. doesn't need to
be reset - therefore the close calls aren't needed. This
works just as well for me...
#!/usr/bin/perl -w

while(<*>) {
    next if /^$0$/;
    open I, $_        or die "$_: $!";
    open O,">$_.bak"  or die "$_.bak: $!";
    print O $_, "\n", (<I>)[0..3];
    #close I, close O;
}

[download]
A few things I picked up from your code:
You used .bak instead of .$$, which makes your solution
portable beyond *nix systems. I like your <*> more than my
glob. Your treatment of the filehandle as though it were an
array is also new to me.

blyman

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Re: Re: Re: Re: Re: Extract lines and output...
by tachyon (Chancellor) on Oct 10, 2001 at 11:10 UTC

    As you say you don't have to close filehandles in many cases. It is just tidy to do so. If you want to do it the more politiacally correct way you use a lexically scoped variable as FH. This is destroyed when you go out of scope and is well scoped. 

    while(<*>) {
      /^$0$/ && next;
      open my $IN, $_           or die "$_: $!";;
      open my $OUT,">$_.bak"    or die "$_.bak: $!";
      print $OUT $_, $/, (<$IN>)[0..3];
}

    [download]

    cheers

    tachyon

    s&&rsenoyhcatreve&&&s&n.+t&"$'$`$\"$\&"&ee&&y&srve&&d&&print

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[d/l]

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