I'm assuming you're using @pattern_list to hold the return values from expect() like this:

@pattern_list = expect "SWBKPT hit for SLOT";
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If that is true, then $pattern_list[0] is the "matched pattern position", $pattern_list[1] is the "error" and $pattern_list[2] is the "successfully matching string". However, to debug this, we need all the values, which is why I asked you to use Data::Dumper.

If you want to print the array values without Data::Dumper, then do something like this:

my @arr = qw( bob sue jane);
print "\@arr = " . join(':', @arr) . "\n";
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my@mybox:~/sandbox
$ ./4.pl
@arr = bob:sue:jane
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The reason all the values are important is because if $pattern_list[4] ("after match") has a value, then that probably means Expect is sending the "\n" before your console program is reading input.

Actually, you know what would be a quicker test of that? Insert a sleep() between your expect() and send() like this:

$expect->expect($timeout,"SWBKPT hit for SLOT");
sleep 2;
$expect->send("\n\n");
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Of course, this test assumes that it takes less than 2 seconds between when the console program prints "SWBKPT hit for SLOT" and when it prints "Cycles : 332".

Here is the Output with Data::Dumper

I have also given the script below

nandi@nandi-laptop:~/begperl$ perl try_expect.pl

Selecting sproc1 CPU


sproc1>
sproc1>loadprg a.out
Endianness of the ELF file:0
.text matched [text segment]
flag = 0x3
.ctors matched [data segment]
flag = 0x3
.dtors matched [data segment]
flag = 0x3
.data matched [data segment]
sproc1>run
Run mode selected
Buffer Empty = 32
Buffer Empty = 32
Buffer Empty = 32
Buffer Empty = 32
Buffer Empty = 28
SWBKPT hit for SLOT 1..!!  PC-Value : 0x124     Blk Count = 1  Cycles 
+: 332
$VAR1 = [
          1,
          undef,
          'SWBKPT hit for SLOT 1..!!  PC-Value : 0x124     Blk Count =
+ 1  Cycles : 332',
          'loadprg a.out
Endianness of the ELF file:0
.text matched [text segment]
flag = 0x3
.ctors matched [data segment]
flag = 0x3
.dtors matched [data segment]
flag = 0x3
.data matched [data segment]
sproc1>run
Run mode selected
Buffer Empty = 32
Buffer Empty = 32
Buffer Empty = 32
Buffer Empty = 32
Buffer Empty = 28
',
          '
',
          bless( \*Symbol::GEN0, 'Expect' )
        ];
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$VAR1 shows that the pattern has matched in 1 poition ie 0 postion of my @match array

undef indicating no error

then comes the successfully_matching_string

then comes the before_match

finally after_match... But here the after match is empty.. So i gussed it must be "\n"

To verify that i did a print with Match_after in between "Hello World"

As it comes out my guess was right

So expect is sending "\n\n" before simulator finishes execution. So I put a sleep as advised.. :( Didnt work either

Here is the script..

#!/usr/bin/perl

use warnings;
use strict;
use Expect;
use Data::Dumper;

chdir '/home/nandi/simulator/' or die "Can't change directory : $!";

my $expect = Expect->new;
my $command = './simulator/pruthvi.out';
my @parameters = qw(-m 4);
my $timeout = 2;
my @pattern_list;
my @match = "SWBKPT hit for SLOT 1..!!  PC-Value : 0x124         Blk C
+ount = 1  Cycles : 332";
$expect->spawn($command,@parameters ) or die "Cannot spawn : $!\n";
$expect->expect($timeout,"Selecting sproc1 CPU");
$expect->send("\n\n");
$expect->expect($timeout,"sproc1>");
$expect->send("loadprg a.out\n");
$expect->expect($timeout,'sproc1>');
$expect->send("run\n");
@pattern_list = $expect->expect($timeout,@match);
print Dumper(\@pattern_list);
#$expect->expect($timeout,"SWBKPT hit for SLOT");
#my $match_after = $expect->after();
#print "Hello $match_after World";
sleep 3;
$expect->send("\n\n");
#$expect->expect("sproc1>");
#$expect->send("dump mem 74010 4 \n");
#$expect->expect("sproc1>");
#$expect->send("quit\n");
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Now what I am supposed to do.. I entered "\n" at the end of string in @match but that too didnt work out.

I think CPAN Expect is not that friendly with Perl compared to Shell. I have no problem running expect in SHELL script.

Hi je44ery I made it.. The script works like charm now..

Thanks for all your valuable input, suggestion, patience and time

So please tell us what was wrong! I'm very curious, and also it will help anyone else who has a similar problem.