Shell Programming and Scripting

empno,ename,sal
123,smith,1000
124,adams,2000

empno,ename,sal,deptno
123,smith,1000
124,adams,2000

awk 'NR==1{print $0",deptno";next} 1'  Input_file

awk 'NR==1{             ##### When first line is getting read.
print $0",deptno";      ##### If above condition is TRUE and then print the first line with "deptno".
next}                   ##### next keyword is awk's built in keyword which helps us to skip all next statements. 
1' Input_file           ##### mentioning 1 here for making condition TRUE, because awk works on condition and then action method, so here we are making condition TRUE and not giving any action so default action will happen which is printing the line.

awk 'NR==1{$0=$0 ",DeptNo"}1' file