sort file1>file1.s 
& sort file2>file2.s 
& join file1.s file2.s 
| perl -anle"print$F[0],' ',$F[1]*$F[2]" 
| sort -n -k 2 > files.merged 
& del file1.s file2.s

c:\test>type files.merged
hello 1
FILE 2
today 6
yes 8
well 12