UNIX for Dummies Questions & Answers

Hi Gurus!

I need to make some file transformations. Please help.

This is my input file. It has four columns with fixed width.

Code:

1   aaa  bbbb   cccc
2   eee  dddd   jjjj
3   fff  gggg   jjjj
4   hhh  iiii   cccc
5   kkk  llll   cccc
6   mmm  nnnn   oooo
7   ppp  qqqq   xxxx
8   rrr  ssss   oooo
9   ttt  wwww   xxxx
10  yyy  zzzz   oooo

Step 1: I need to transform it like this. This is formed by sorting the fourth column and its corresponding line should go along with the arrangement upon sorting.

Code:

1   aaa  bbbb   cccc
4   hhh  iiii   cccc
5   kkk  llll   cccc
2   eee  dddd   jjjj
3   fff  gggg   jjjj
6   mmm  nnnn   oooo
8   rrr  ssss   oooo
10  yyy  zzzz   oooo
7   ppp  qqqq   xxxx
9   ttt  wwww   xxxx

Step 2: The result of step 1 will also be processed to have the following result shown below. This is done by transforming the third column to be a row with reference to the unique value in the fourth column.
With reference to the output of Step1, the data in the fourth column is cccc, so take take value in the 3rd column for the same line with a value of cccc in the fourth column...
if the 4th column's data is changed; example from cccc to jjjj; move to the next line and cascade corresponding values from the 3rd column of the input

Code:

bbbb,iiii,llll
dddd,gggg
nnnn,ssss,zzzz
qqqq,wwww

I hope somebody can help me. Thanks in advance!

Code:

sort -k4 infile | awk '{print $4, $3} ' |
 awk '{arr[$1]=arr[$1] " " $2} END {for (i in arr) {print arr[i] }} '

This sorts , pulls out the fields of interest, aggregates them, then prints thm.