Extending runrig's answer to cover the case where "blank" could include whitespace characters (as merlyn's answer already does, negatively): Use /^\s*$/
As in: 

while (<>) {
    print "blank line detected\n" if /^\s*$/;
}

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In reply to Re: How do I test for a blank line when reading from a file? by thanos1983
in thread How do I test for a blank line when reading from a file? by bravismore

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