or download this
$ pm_1168253_reformat_input_WITH_FILES_PRODUCTON.pl pm_1168253_reforma
+t_input_INPUT.txt pm_1168253_reformat_input_INPUT_CLONE.txt; cat pm_1
+168253_reformat_input_INPUT.txt__OUTPUT.txt; cat pm_1168253_reformat_
+input_INPUT_CLONE.txt__OUTPUT.txt
H123456,20151209,THIS IS A TEST TO COMBINE ALL MY MATCHING LINES INTO
+THE FIRST LINE THAT MATCHES.
...
H123456,20151209,THIS IS A TEST TO COMBINE ALL MY MATCHING LINES INTO
+THE FIRST LINE THAT MATCHES.
H654321,20151209,MATCH LINES FOR THIS ACCT INTO THE TOP LINE OF THE AC
+CT
H432165,20151209,SINGLE LINE FOR THIS ONE