Note that RudiC's and Scrutinizer's suggestions both depend on the fact that the orgX and orgXX strings in file2 are distinct. Had file2 also contained the line:

Code:

org2=japan

both of those suggestions might randomly have resulted in japan9 appearing in the output instead of america, japan3 appearing instead of europe, and japan2 appearing instead of china.

If this might be a problem for you, you would either need to be sure that all of your orgXX strings are the same length or sort your orgXX values by decreasing numerical value of XX and process the substitutions from beginning to end in sequence (like Scrutinizer did) instead of using for (r in REP) (like RudiC did).

And, if using Scrutinizer's code and a single orgXX string might occur more than once in a line of input (which does not happen in your sample), you would need to use gsub() instead of sub() to get the desired results.