UNIX for Dummies Questions & Answers

Hi friends,

i am trying to diff two files and the result will be passed to awk and this will get the first 20 characters in every line and put the result in a file.... but i can't generate an output.

Code:

$ cat file1.txt
1
2
3
4
5
$ cat file2.txt
1
2
3
4

the line of command is:

Code:

   
$ diff file1.txt file2.txt | awk '$1 ~ /^</ {printf("%-'"20"'s\n", $2)}' > list.txt

and the list.txt is a zero byte file (empty)..... it should contain one line with a value of '5' followed by19 spaces


Please help

I think your regex isn't working. You can make it a lot simpler.

Code:

$ diff file1.txt file2.txt  | awk '/^</ { printf("%-20s\n", $2) }'

It is still not working, the difflist.txt is still empty...

the output of the diff is in this format:

Code:

3a4
> 5

then awk will do the rest supposedly.

---------- Post updated at 12:02 PM ---------- Previous update was at 11:31 AM ----------

i was able to do it but not with a one liner command, i'll post the code for the benefit of other researchers

Code:

diff file1.txt file2.txt > difflist
grep '>' difflist | $AWK '{print $2}' > list.txt