Example file

table 1  table 2  key 1  key 2
-------  -------  -----  -----
apple    bug      unid1  unid2
apple    cat      unid1  unid3
bug      dog      unid2  unid4
apple    dog      unid1  unid4

##</code><code>##

Example 1:

[dmathis@wildman dmathis]$ ./script apple bug

The output:

apple a
join bug b on a.unid1 = b.unid2

##</code><code>##

Example 2:

[dmathis@wildman dmathis]$ ./script apple dog

The output:

Option 1:
apple a
join bug b on a.unid1 = b.unid2
join dog d on b.unid2 = d.unid4

Option 2:
apple a
join dog d on a.unid1 = d.unid4