Question

A variable named RestrictedNames holds the list of restricted user names. SplitNames is an array variable which holds the complete set of user name. Now I have to check whether current name is found in RestrictedNames variable like using instr.

@SplitNames = ("naag algates","arvind singh","abhay avasti","luv singh","new algates") and now i want to block all the surnames which has "singh" ,"algates" etc.

    @SplitNames = ("naag algates","arvind singh","abhay avasti","luv singh","new algates")
    $RestrictedNames="tiwary singh algates n2 n3 n4 n5 n6";
    for(my $i=0;$i<@SplitNames;$i++)
    {
        if($RestrictedNames =~ m/^$SplitNames[$i]/ ) //google'd this condition, still fails
        {
              print "$SplitNames[$i] is a restricted person";
        }
    }

Answer 1

You should modify this line:

if($RestrictedNames =~ m/^$SplitNames[$i]/ )

to

if($RestrictedNames =~ m/$SplitNames[$i]/ )

^ looks for a match from the beginning.

For more details about perl metacharacters, see here

EDIT:
If you need blocking based on surnames, try this code in the for-loop body.

my @tokens = split(' ', $SplitNames[$i]); # splits name on basis of spaces
my $surname = $tokens[$#tokens]; # takes the last token
if($RestrictedNames =~ m/$surname/ )
{
      print "$SplitNames[$i] is a restricted person\n";
}