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videlete-row

vi delete line with second occurence of pattern

I have a large file and many lines are duplicated. I'm trying to delete lines with every second occurrence of a pattern. Did tried searching similar question on SO but no luck.

I can delete all lines matching pattern with ":g/pattern/d" but don't want to loose data.

Sample pattern to delete "John-------Doe"

Sample data:  
Time--------FName---------LName

11:05-------John------------Doe   
11:05-------John------------Doe  
11:06-------Michael---------Lawrence  
11:06-------Michale---------Lawrence

Expected result:  
11:05-------John------------Doe   
11:06-------Michael---------Lawrence
Solution

  • %!uniq if file contains only sorted data
    %!sort -u if file contains only data, but unsorted
    S,E!uniq where S is starting line number of data, E is ending line number of data , assuming data is sorted
    S,E!sort -u where S is starting line number of data, E is ending line number of data, for unsorted data