this task can be accomplished with a perl one-liner:

but if you'd like to make it a script, with full error checking, i might do something like:

#!/opt/perl5/bin/perl5.005 -w
use strict;
use warnings;
$|++;

## process each file passed on command line
for my $file ( @ARGV )
{
  ## open the file for reading
  open( RC => "<", $file )
    or die "Can't open $file";

  ## print the program name and current file to be processed
  print "$0: $file\n";

  ## print errors and warnings
  while(<RC>)
  { print if /error|warning/i }
  close RC;
}
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~Particle *accelerates*