How to get a substring after the last underscore (_) in unix shell script

Question

I have a String like this

this_is_test_string1_22
this_is_also_test_string12_6

I wanted to split and extracts string around the last unders

Answer 1

Using awk:

$ awk 'BEGIN{FS=OFS="_"}{last=$NF;NF--;print $0" "last}' < this_is_test_string1_22
> this_is_also_test_string12_6
> EOF
this_is_test_string1 22
this_is_also_test_string12 6