Thank you so much!! your suggestions really helped. I apologize for the formatting errors. I hope its not too bad this time.

Can I ask you one more question. With this input file (below):
gene_a gene_b
gene_b gene_a

I get the following output:
gene_a gene_b

If the input file is something like this:
gene_a gene_b
gene_b gene_a
gene_c gene_a
gene_a gene_c
gene_c gene_b
gene_b gene_c

Then I want the program to output the following:
gene_a gene_b gene_c

instead of:
gene_a gene_b
gene_b gene_c
gene_c gene_a

The thing is I am looking for pairs for which column[0] is equal to column1 and vice versa. This can happen for any combination of numbers (as I showed with three above a, b and c). Can you provide your suggestion in this case. I would really really appreciate it!

Thanks

BH

In reply to Re^2: how to compare column 1 to column 2 and vice versa from multiple rows. by BhariD
in thread how to compare column 1 to column 2 and vice versa from multiple rows. by BhariD

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