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I need to sort a flat file by third column leaving first column intact [First column is already sorted] (in linux). (second column may change)
Example i/p file:-
b:di:wave
b:di12:red
b:di12:wave
b:di06:pir
Should look like:-
b:di06:pir
b:di12:red
b:di12:wave
bast:di:wave
I tried several sorting options but I could sort only by second column but not third.
Can someone please help ?
813
No, by default sort columns are blank separated, they are not character columns, to sort on the 3rd character column, the syntax would be: sort -k 1.3,1.3 .
5. -k Option: Unix provides the feature of sorting a table on the basis of any column number by using -k option. Use the -k option to sort on a certain column. For example, use “-k 2” to sort on the second column.
Use the -k option to sort on a certain column. For example, use " -k 2 " to sort on the second column. In old versions of sort, the +1 option made the program sort on the second column of data ( +2 for the third, etc.).
Sorting by multiple columns is similar to sorting by a single column. To sort on a range of columns, simply specify the start and end columns in the column range to use for sorting.
Try this:
sort -t: -k1,1 -k3 data.txt
gives:
bast:disp-san-d5-06:piranha
bast:display-san-12:redbird
bast:display-san-07:waverider
bast:display-san-12:waverider
This will sort with the 1st field as primary key, and the 3rd field as secondary key splitting the line into fields by :
Details:
data.txt contains the 4 lines from your post.
You can specify multiple fields as sorting keys, see the man page
-k1,1 means sort on the first field (start at field 1 and end at field 1, otherwise it would continue using the rest of the line for determining the sort)
-k3 means sort on the 3rd field as secondary key. Since there are no other fields behind it is not necessary to specify -k3,3 but it wouldn't hurt either.
-t: means delimit fields in lines with the : character, otherwise blank is used by default
More information see this SO question Sorting multiple keys with Unix sort and the sort man page
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