use strict;

my $fileglob  = shift || '*.pl';
my $pattern   = shift || 'hello';
my $keeplines = shift || 3;

for my $file (<${fileglob}>) { 
  unless(open(IN, $file)) { warn "Can't read from $file: $!"; next; }
  my @lines;
  while(<IN>) { 
    push @lines, $_;
    shift @lines if(@lines > $keeplines);
    if(/$pattern/i) {
      print "--- From $file:---\n@lines\n"
    }
  }
}