I guess you've understood this, but your attempt to escape the star didn't work:

$ perl -wE 'say "\*E"'
*E
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The double-quoted string ate the backslash, the regex just sees *E.

There are several solutions:

# ugly, but works:
my $failmsg = "\\*E";
if (/$failmsg/) { ... }

# nicer, since you don't have to do the escaping yourself
$failmsg = '*E';
if (/\Q$failmsg\E/) { ... } 

# if you want to quote regular expressions, do this:
$failmsg = qr{\*E};
if ($_ =~ $failmsg) { ... }
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This last solution is nice because it accepts modifiers, so for example if you want to do a case-insensitive match, you can write $failmsg = qr{\*E}i;.

And some other ways:

my $failmsg = '\*E';    # Single quotes prevent interpolation
my $failmsg = '[*]E';   # Character class makes it not special.

my $failmsg = "*E";
if (index($_, $failmsg) >= 0)  # Don't use a regexp.
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moritz, Thanks for the quick reply. But, what surprises me is double-quotes eating up the backslash. This is very arbitrary, unintuitive(at least to me), and also undesirable. Do you know if this is documented anywhere? Thanks for all the help.

It's not undesirable at all. In double quotes, the backslash is indicates the start of an escape allowing "\n" to mean newline, "\"" to mean a double quote, etc. Double quotes are documented in perlop.

You're just using the wrong tool.

$failmsg = qr/\*E/;
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See perldoc perldata

Documented in various places. perlop, sections Quote-Like Operators and Gory details of parsing quoted constructs, and perldata, section Scalar value constructors.

$failmsg = '\*E';
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Or, double up the backslashes

$failmsg = "\\*E";
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You might also consider using quotemeta or the \Q and \E operators.

My other thought here, because you don't appear to need the power of a regular expression (you are just looking to see if one string contains another), index will give you that information with much less overhead.