CODEWITHSUNDEEP
bashshellawk
imbenzene
imbenzene

Reputation: 31

Shell Script to generate specific columns as separate files

I want to print my first column and 2nd column from radius.dat and save it to rad.2.out, first column with 3rd column as rad.3.out, and so on.

However, this script doesn't seem to be working. 

#!/bin/bash 
for i in {2..30}
do
awk '{print $1, $i}' radius.dat > 'rad.'$i'.out'
done

Upvotes: 0

Views: 80

Answers (2)

jaypal singh
jaypal singh

Reputation: 77185

Using awk you can do:

awk '{for(i=2;i<=NF;i++) print $1, $i > ("rad."i".out")}' radius.dat

The only caveat is that it will lead to many open files, it might not be a problem if you are not on ancient awk.

What we are doing here is basically using an iterator and iterating through columns starting from the second and printing the first column and the iterator during each iteration to an output file using the naming convention as you desire.

Update (based on your comment to your question):

If you notice too many open files error then you can do:

awk '{
    for (i=2; i<=NF; i++) { 
        print $1, $i >> ("rad."i".out"); 
        close("rad."i".out")
    }
}' file

Notice in the second option we use >> instead of >. This is due to the fact that we are closing the file after each iteration so we need to make sure we don't overwrite the existing files.

Upvotes: 2

Eugen Rieck
Eugen Rieck

Reputation: 65342

Your quoting is quite off ... awk never gets the column. Try this:

#!/bin/bash 
for i in {2..30}; do
  awk "{print \$1, \$$i;}" radius.dat > "rad.$i.out"
done

Upvotes: 0

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