Combining two awk commands in single command

Question

I want to combine these two command and want to invoke single command

In first command i am storing 4th column of x.csv(Separator ,) file in z.csv file.

awk -F, '{print $4}' x.CSV > z.csv

In second command, i want to find out unique first-column value of z.csv(Separator-space) file.

awk -F\  '{print $1}' z.csv|sort|uniq

I want to combine these two command in single command,How can i do that?

Answer 1

Assuming that the content of z.csv is actually wanted, rather than just an artefact of the way you're currently implementing your program, then you can use:

awk -F, '{ print $4 > "z.csv"
           split($4, f, " ")
           f4[f[1]] = 1
         }
         END { for (i in f4) print i }' x.CSV

The split function breaks field 4 on spaces, and (associative) array f4 records the key value. The loop at the end prints out the distinct values, unsorted. If you need them sorted, you can either use GNU awk's built-in sort functions or (if you don't have an awk with built-in sort functions) write your own in awk, or pipe the output to sort.

With GNU awk, you can replace the END block with:

         END { asorti(f4); for (i in f4) print f4[i] }

If you don't want the z.csv file, then (a) you could have used a pipe in the first place, and (b) you can simply remove the print $4 > "z.csv" line.

Answer 2

Pipe the output of the first awk to the second awk:

awk -F, '{print $4}' x.CSV | awk -F\  '{print $1}' |sort|uniq

or, as Avinash Raj suggested,

awk -F, '{print $4}' x.CSV | awk -F\  '{print $1}' | sort -u