Concatenate/merge columns

Question

File( ~50,000 columns)

A1 2 123 f f j j k k  
A2 10 789 f o p f m n

Output

A1 2 123 ff jj kk  
A2 10 789 fo pf mn

I basically want to concatenate every two columns into one starting from column4. How can we do it in awk or sed?

Answer 1

It is possible in awk. See below

:~/t> more test.txt
A1 2 123 f f j j k k

:~/t> awk '{for(i=j=4; i < NF; i+=2) {$j = $i$(i+1); j++} NF=j-1}1' test.txt
A1 2 123 ff jj kk

Sorry just noticed you gave two lines as example...

:~/t> more test.txt
A1 2 123 f f j j k k
A2 10 789 f o p f m n

:~/t> awk '{for(i=j=4; i < NF; i+=2) {$j = $i$(i+1); j++} NF=j-1}1' test.txt
A1 2 123 ff jj kk
A2 10 789 fo pf mn