Shell Programming and Scripting

Hi I'm new to this forum and I'm a beginner when it comes to shell programming and awk programming. But I have the following problem:

I've a list like this:

1
2
3
4
5
6
7
8

Either from a file or output from a command. What I would like to do is to arrange these values into x columns with values in each column like this:

1 2 3 4
5 6 7 8

Where x specifies how many columns I would like. Then I would like to add all the values from column 1 and divide it with the numbers of rows (in this case 2).

forgot something: this is for a bourne shell script. Is it possible to have x as a variable input when running the script?

Or is it possible to, instead of making columns, to add every x element in the list and then take an average?

Code:

awk -v var=4 -f sample.awk inputfile

where sample.awk is

Code:

(NR % var ) == 0 { sum+=$0; cnt++}
END {print sum, cnt }

This adds every 4'th element is the list.

If you want the count starting from the first column in the list, change the sample.awk to

Code:

BEGIN { row_cnt=1 }
(NR % row_cnt ) == 0 { sum+=$0; cnt++; row_cnt+=var }
END {print sum, cnt }

Try this:

Code:

awk -v INPUT=$INPUT '
BEGIN { ORS=""}
{

print $0 " "
if (( NR % INPUT ) == 0) {
print "\n"
count++
}

if (( NR % INPUT ) == 1) 
sum += $0

}

END { 
 op = sum/count
print op }' Filename

cat file | xargs -n <number of items in a row>

Code:

"/home/tdreader" > cat t.txt
1 2 3 4 5 6 7 8 9 12 12 32 5 66 56 343 8 875 434 0
"/home/tdreader" > cat t.txt | xargs -n 3
1 2 3
4 5 6
7 8 9
12 12 32
5 66 56
343 8 875
434 0

If it is a file with one number in a line,
go for this

Code:

cat filename | tr '\n' ' ' | xargs -n 3

I really appreciate the help.

I like the xargs thing. Is it then possible to add each element in a column and divide it by the numbers of elements in the column.

I've used this command:

awk '{ sum+=$1/2 }{ sum1+=$2/2} END { print sum sum1 }'

But $1/2 where the 2 should be a variable (the number of elements in the column).

Also ranj@chn I didn't get your script to work, I must be doing something wrong. I just copied what you wrote and tried to run it with:

awk -v var=2 -f reader2.awk testfile.txt

But I only get errors.

And I also tried to run ahmedwaseem2000's program but I didn't get that to work either. I really sorry but I'm a real "noob" at this. But the help you are giving me are invaluable.

Do post the errors and the Unix box that you are connected to - o/p of

Code:

uname -a

That could help identifying the issue. You must use 'nawk' instead of awk on Solaris and 'gawk' if its Linux.

what is the error you are getting? its working perfectly fine for me. see below


3 is the (1 + 5 )/2=3

YOU NEED TO ASSIGN VALUE OF "INPUT" VARIABLE before running the code else it will give you the "division by zero in modulus" like run INPUT=4 before running the code.