I followed ur suggestion and used Devel::Trace. I found that code stops here after looping through many files. The perl script just goes through files and counts if certain words are present and then records the file names to a csv file. Here is the part that is causing the problem.

Again, the file runs fine up to a point that the csv file is about a size of 700KB and then dies

According to Devel::Trace this is where it stops

 if($data=~m/${query}/io) {
      $match_found=1;
      $fcount=()=$data=~m/(?^:\n.*(?:(?:(?:(?:authoritative|revenue\s+
+recognition|invaluable\s+practical|valuable|regulatory|technical|unde
+r\s+the|staff's|judicial|SEC|FDA|Treasury(?:\s+Department)?|specific|
+implementation|their|government|any\s+ruling|college|absent|\s+his|in
+terim|intrepretive|transition|administrative|procedural|related|appli
+cable|accounting|definitive|supreme\s+court|superceding|IRS|Internal\
+s+Revenue\s+Service|valued|EITF\s+accounting)|provides?\s+guidance\s+
+(?:on\s+(?:how)?|for)\s+(?:to\s+identify|uncertain\s+tax|whether)|(?:
+interpretation|permits|knowledge|regulations|successor\s+statutes|pol
+icy(?:\s+statements)?)\s+(?:or|\,)|board\s+will\s+continue\s+to\s+pro
+vide\s+guidance|guidance\s+requiring\s+the\s+credit|(?:directive|navi
+gation|exemption|practice|judgments|doctrine|forecast),|FD\s+Disclosu
+re\s+of\s+Form\s+8-K\s+in\s+accordance\s+with\s+guidance|guidance\s+d
+ocument\s+promulgated|seek\s+guidance\s+from|employee\s+handbook\s+fo
+r|(?:SAB\s+101|FIN\s+48|EITF\s+00\-14|SOP98\-\d|SFAS\s+\d\d\d?)\s+(?:
+also\s+)?provides\s+guidance(?:\s+on\s+whether|related)|Item\s+\d\d?\
+s+pursuant\s+to|(?:other|applicable)\s+guidance\s+issued|according\s+
+to\s+the\s+guidance\s+contained|provide\s+guidance\s+to\s+directors|r
+eceiving)\s+guidanc|(?:\"projection\"|\"intend\")(?:\s+and\s+|\,)"out
+look"|company\s+follows\s+the\s+guidance\s+of|guidance\s+should\s+be\
+s+applied\s+prospectively|provides\s+guidance\s+for\s+using\s+fair\s+
+valu)e|guidance\s+(?:(?:from\s+(?:the\s+)?(?:FDA|Financial\s+Accounti
+ng\s+Standards\s+Board)|(?:counsel|advice|information|circular|regula
+tion|code)\s+and|(?:prescribed|set\s+forth|issued)\s+by(?:\s+the\s+(?
+:Department|Treasury|AICPA|FASB|SEC))?|(?:action|policy|orders)\s+or)
+\s+guidance|(?:and\s+rules|promulgated(?:\s+thereunder)?|in\s+SFAS)|(
+?:provided|issued)\s+by\s+(?:the\s+)?(?:SEC|Securities\s+and\s+Exchan
+ge\s+Commission|Internal\s+Revenue\s+Service|Secretary|United\s+State
+s|Financial\s+Accounting)|(?:on|of|in)\s+(?:de\-recognition|APB\s+25|
+S?FAS\s+No\.\s+144|SFAS\s+No\.\s+(?:150|13|123)|ARB|SEC\s+Release|SOP
+\s+90-7|Emerging\s+Issues|SAB\s+101|determining\s+whether\s+multiple)
+|(?:is\s+effective|which\s+allowed)|(?:comply\s+with\s+guidance\s+set
+\s+forth\s+by|guidance\s+available\s+from)\s+the\s+(?:treasury|intern
+al\s+revenue\s+service|IRS|SEC|FASB|AICPA)|disseminated\s+by\s+the\s+
+SEC|additional\s+guidance\s+to\s+physicians|FASB\s+issued\s+final\s+g
+uidance|informed\s+of\s+the\s+guidance\s+relating|on\s+(?:recognizing
+|the\s+application|the\s+identification|when\s+to\s+assess|accounting
+\s+for\s+revenue))|(?:regarding\s+management's\s+plans,\s+goals,\s+ex
+pectations,\s+guidance|To\s+obtain\s+guidance\s+on|for\s+additional\s
++guidance\s+on\s+which\s+number\s+to\s+repor|under\s+the\s+guidance\s
++and\s+(?:advice\s+of|Procedures|leadership|counsel|support)|company\
+s+follows\s+the\s+guidance\s+set\+forth\s+in\s+statemen|(?:future\s+s
+tatutes|ordinances|orders|rules|regulations),\s+guidance|pursuant\s+t
+o\s+SEC\s+guidance|Outlook\s+Pointe|guidance\s+line\s+of\s+credi)t|ou
+tlook\s+for\s+any\s+rating|(?:rating|if\s+on\s+negative|Microsoft|sug
+gesting\s+an|may\s+contain\s+statements\s+about\s+future\s+events\,|b
+usiness\s+conditions\s+and\s+the)\s+outlook|guidance\s+(?:to\s+approv
+e|facility)|the\s+guidance\s+from\s+the\s+OCA|Internal\s+Revenue\s+Se
+rvice\s+has\s+issued\s+guidance|(?:wisdom|technical\s+assistance|nece
+ssary\s+supervision|leadership)\s+and\s+guidances?|(?:current|other)\
+s+guidance\s+(?:under|from)|assumes\s+guidance\s+of\s+(?:the|a)\s+(?:
+company|board|talented\s+team|compensation)|guidance\s+(?:system|soft
+ware|technology)|forward\s+to\s+his\s+guidance|guidance\s+received\s+
+by\s+the\s+Company|section\s+409A\s+transition\s+guidance|absent\s+gu
+idance\s+from\s+the\s+(?:Commission|government)|Statements\s+in\s+thi
+s\s+press\s+release\s+concerning\s+the\s+company's\s+business\s+outlo
+ok|guidance\s+regarding\s+the\s+acceptance\s+of\s+gifts))
                  /xig;  
}
[download]

I built this regex using regex::assemble. Please let me know if there are better ways to speed up regex. Thank you again!