AWK, deleting and comparing lines

[David Scherrer]

Dear all,

I would like to use AWK to delete lines of a file that have a "C" in their
first field as well as the closest foregoing line containing a "T" in the
first field. When there are 2,3,4,... "C"-lines after each other I would
also like to delete the closest 2,3,4,... foregoing "T"-lines.

Additionally it would be great if I could compare the "C" and the "T" line
and condition deletion upon on the comparison result. E.g. delete the
closest forgoing "T"-line above with fields 4 and 6 the same as the
"C"-line.

For illustrating purposes I copy pasted a short sequence of lines and marked
the C lines red and the corresponding T lines yellow.

I'm very grateful for any help!

Many thanks,
David


T,N,N,2000000,A,98.025,3.136519,20020702,14:19:20,,98.025,3.136519
T,N,N,2500000,A,98.1503,,20020702,14:20:36,,98.1503,
C,N,N,2500000,A,98.1503,,20020702,14:20:36,,98.025,3.136519
T,N,N,2500000,A,98.1503,,20020702,15:14:27,,98.1503,
T,N,N,1500000,A,98.8,3.083,20020703,9:45:10,3.083,98.8,3.083
T,N,N,1000000,A,100.1067,2.953,20020705,9:31:39,2.512,101.13,2.512
T,N,N,500000,A,101.13,2.512,20020705,10:47:51,2.512,101.13,2.512
T,N,N,3900000,A,85,4.135633,20020708,10:31:43,4.114726,85.25,4.114726
T,N,N,3900000,A,85,4.135633,20020708,10:31:43,4.114726,85.25,4.114726
C,N,N,3900000,A,85,4.135633,20020708,10:31:43,4.114726,85.25,4.114726
C,N,N,3900000,A,85,4.135633,20020708,10:31:43,4.114726,85.25,4.114726
T,N,N,1500000,A,100.875,2.621247,20020708,16:11:18,2.621247,100.875,2.621247
T,N,N,710000,A,100.3156,,20020709,10:34:23,,100.3156,
T,N,N,285000,A,100.875,2.620812,20020709,11:15:58,2.620812,100.875,2.620812
T,N,N,60000,A,99.75,3.01699,20020710,10:45:48,3.01699,99.75,3.01699