How to sort groups of lines together?

Question

I have this file:

rs1    1    ADD     0.7     0.75     0.45
rs1    1    VAR     0.4     4.53     0.06
rs1    1    USER    NA      1.96     0.37
rs2    2    ADD     1.5     0.25     0.23
rs2    2    VAR     0.4     4.86     0.03
rs2    2    USER    NA      1.73     0.05
rs3    3    ADD     0.29    0.76     0.97
rs3    3    VAR     0.44    3.95     0.09
rs3    3    USER    0.96    5.41     0.01

For each value in $1, there are three lines with ADD, VAR, USER in $3. I want to sort (reverse sort) the file based on the $6 values for lines with USER in $3. The question is that how I could do this AND at the same time keep the corresponding lines with ADD, VAR next to the sorted lines. I don't need the other two lines to be sorted; I just need them to be next to the sorted line.

Desired output:

 rs3    3    ADD     0.29    0.76    0.97
 rs3    3    VAR     0.44    3.95    0.09
 rs3    3    USER    0.96    5.41    0.01
 rs2    2    ADD     1.5     0.25    0.23
 rs2    2    VAR     0.4     4.86    0.03
 rs2    2    USER    NA      1.73    0.05
 rs1    1    ADD     0.7     0.75    0.45
 rs1    1    VAR     0.4     4.53    0.06
 rs1    1    USER    NA      1.96    0.37

I have tried this code, but it only sorts based on the $6 values in USER lines:

cat File | sort -k1 | uniq | sort -g -k6 > Output

Thank you

Answer 1

This is a bit messy but does what you want:

paste - - - < File | sort -k18,18g | xargs -n 6

The problem with the input format is that sort has no way to operate on groups of input lines, so you need to turn each group into one line, sort it, then turn it back. This only works if the input "USER" line is always last in the group.

Answer 2

Here's a one-liner for Ruby :)

ruby -e 'File.open(ARGV.shift).readlines.entries.group_by{|e| e.split[1]}.sort.reverse.each{|e| puts e[1]}' file

Output:

rs3    3    ADD     0.29    0.76     0.97
rs3    3    VAR     0.44    3.95     0.09
rs3    3    USER    0.96    5.41     0.05
rs2    2    ADD     1.5     0.25     0.23
rs2    2    VAR     0.4     4.86     0.03
rs2    2    USER    NA      1.73     0.01
rs1    1    ADD     0.7     0.75     0.45
rs1    1    VAR     0.4     4.53     0.06
rs1    1    USER    NA      1.96     0.37