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Shell Programming and Scripting

Sequential extraction of first row

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# 1  
Old 11-08-2012
Sequential extraction of first row
I do have a large text file (tab delimited) of the following format


Code:
RT_1 34 67
RT_1 9 10
RT_1 98 56
RT_2 09 89
RT_2 23 45
RT_2  90 76
RT_3  98 21
RT_4 23 90
RT_4 67 90
RT_4 79 23
RT_5 8 9

I want to parse every first row (complete row), whenever a new value in column 1 (here RT_1, RT_2, RT_3, RT_4, RT_5) comes up. The first column is sorted.

Code:
RT_1 34 67
RT_2 09 89
RT_3  98 21
RT_4 23 90
RT_5 8 9

Please let me know how to do this in awk or sed.
Last edited by Scott; 11-08-2012 at 06:10 PM.. Reason: CODE TAGS .... .... ....
# 2  
Old 11-08-2012
try:
Code:
awk 'a[$1]++ ? 0 : 1' infile

This User Gave Thanks to rdrtx1 For This Post:
Lucky Ali
# 3  
Old 11-08-2012
Code:
awk '!arr[$1]++' inputfile > outputfile

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