Shell Programming and Scripting

i need to compare three files in unix
a.txt b.txt c.txt
1 2 1
2 5 3
4 6 5
5 6
6

i need to insert a blank line in the file if i don't find a match
and put the items at the same column if found a match
The items in the files appear in sorted order

The output should be
a.txt b.txt c.txt
1 blank 1
2 2 blank
blank blank 3
4 blank blank
5 blank 5
6 6 6

What have you tried, please share, so that someone can guide you.

Rakesh i have three columns in a file where numbers come in sorted order

1 2 1
2 5 3
4 6 5
5 6
6


Now i want to compare first item, second item third item and so on in each column
if i get a match in all three i let all the items remain as it is

eg in above

6 6 6

if i don't get a match i let the minimum of this at the same place and shift the other(s) down.

eg in the first line

1 2 1

i need to get

1 blank 1
blank 2 blank

so the total output of the above input file should look like

1 blank 1

2 2 blank

blank blank 3

4 blank blank

5 5 blank

6 6 6

i have wriiten blank so that it appear formatted here

I understood your requirement already.
Have you tried some code yourself? If yes, please share.

---------- Post updated 06-19-09 at 11:42 AM ---------- Previous update was 06-18-09 at 05:17 PM ----------

To start with, you can use the below code for comparing two files and inserting blanks.

Code:

sdiff file1 file2 | awk '{
if ($1==">")
   $1="                                                                  "
if ($2=="<")
   $2=" "
print
}'

Thanks Rakesh i had tried some solutions but the script for it is turning out to be too long , also the diff ,sdiff, comm all work for two files very well but i am looking to compare three files, if i bring third file into comparison the output of sdiff turns out to be of no use

---------- Post updated at 04:57 AM ---------- Previous update was at 02:48 AM ----------

Rakesh i was able to think of a solution where in
cat a.txt b.txt c.txt > d.txt
sort d.txt | uniq > test

then run a for loop in test and check for the item in each of a.txt b.txt c.txt
if the item not present insert a blank in the file

Thanks for you response and inputs regarding the same.