Add a new column to the file

Question

How can I add a new column to a file with awk codes?

original.file

F1 F2 F3 ..F10 

add F11 to original.file

F1 F2 F         


        

Answer 1

If you want to add a column to a file, you can do the following.

remark: We assume that the field separator FS equals to the string "fs". You can replace this by anything, or if you just use as field separator, you can remove the BEGIN{FS=OFS="fs"} part in any of the following solutions.

add a column at the beginning:

awk 'BEGIN{FS=OFS="fs"}{print value OFS $0}' file

add a column at the end:

awk 'BEGIN{FS=OFS="fs"}{print $0 OFS value}' file

add a column before column n:

awk 'BEGIN{FS=OFS="fs"}{$n = value OFS $n}1' file

add column after column n:

awk 'BEGIN{FS=OFS="fs"}{$n = $n OFS value}1' file

add a column before each of column n1 < n2 < ... < nm: (start at the back)

awk 'BEGIN{FS=OFS="fs"; split("n1,n2,n3,...,nm",a,",")}
     {for(i=m;i>0;--i) $(a[i]) = value OFS $(a[i])}1' file

or for different values

awk 'BEGIN{FS=OFS="fs"; split("n1,n2,n3,...,nm",a,","); split("value1,value2,...,valuem",v,",")}
     {for(i=m;i>0;--i) $(a[i]) = v[i] OFS $(a[i])}1' file

add a column after each of column n1 < n2 < ... < nm: (start at the back)

awk 'BEGIN{FS=OFS="fs"; split("n1,n2,n3,...,nm",a,",")}
     {for(i=m;i>0;--i) $(a[i]) = $(a[i]) OFS value}1' file

or for different values

awk 'BEGIN{FS=OFS="fs"; split("n1,n2,n3,...,nm",a,","); split("value1,value2,...,valuem",v,",")}
     {for(i=m;i>0;--i) $(a[i]) = $(a[i]) OFS v[i]}1' file