in reply to write and read the same file not display the output

Another option is to close the file, and then reopen it for reading:

use strict;
use warnings;

open my $fo, '+>>', "outfile.txt" or die "Error:$!\n";
print $fo "how r u\n";
print $fo "hey suresh their\n";
print $fo "in bangalore\n";
close $fo;

open my $fi, '<', "outfile.txt" or die "Error:$!\n";
while ( my $line = <$fi> ) {
    print "$line";
    my $a = index( $line, "suresh" );
    print "$a\n";
}

close $fi;

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Output:

how r u
-1
hey suresh their
4
in bangalore
-1
how r u
-1
hey suresh their
4
in bangalore
-1

[download]

I'm assuming your meant index instead of substr.

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Re^2: write and read the same file not display the output
by ulaksh (Acolyte) on Sep 05, 2012 at 00:53 UTC

    thanks for the help

    Now I am trying in different way, please correct if I am wrong

    while ( <$fi> ) {
    #print "$_";
         
             my $a = $1 if /(^$name$)/;
             print $a;
  
}

close $fi;

    [download]

    But when I run the file output show nothing, and it shows me some message, I am not getting where is the issue please see the below output

    perl readwritefile.pl
Use of uninitialized value $a in print at readwritefile.pl line 15, <$
+fi> line 1.
Use of uninitialized value $a in print at readwritefile.pl line 15, <$
+fi> line 2.
Use of uninitialized value $a in print at readwritefile.pl line 15, <$
+fi> line 3.

    [download]
[reply]
[d/l]
[select]

      Hello ulaksh, Im guessing youve commented out your print "$_"; on purpose there. Anyway your getting yelled at because when the regex doesnt make a match, $a is not getting defined at all, so it is still undefined. You then try to use it on the next line print $a; You cant print $a because it has no value. It is undefined at the moment. This is also the reason your not getting anything printed to screen. maybe you can try this instead? : 

      print $1 if /^($name)$/;

      [download]
[reply]
[d/l]

        Good eye, Rudolf! Did you mean:

        print $1 if /^($name)$/;

        [download]
[reply]
[d/l]

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