Need suggestion for following. Have two files myfile and responsefile. First file myfile.txt user=myname user_1=yourname group=mygroup group_1=yourgroup second file responsefile.txt #Please fill details user= #user_1= #user_2= #Please fill details group= #group_1= #group_2= Based on myfile.txt data update responsefile.txt as below and the file responsefile.txt is lenghty of about 604L, 16481C. Result output responsefile.txt #Please fill details user=myname user_1=yourname #user_2= #Please fill details group=mygroup group_1=yourgroup #group_2= If you observe myfile above, I want to match user= in responsefile, then update as user=myname, same applies for group=. Then match user_1= and group_1= which is hashed or commented in responsefile, update as user_1=yourname and group_1=yourgroup. Should not remove hash or uncomment for others in file. I tried this awk -F= 'NR==FNR{a[$1]=$0;next}$1 in a{$0=a[$1]}1' myfile.txt responsefile.txt Please suggest thanks in advance.