pairsamtools merge single file no action?

[sergpolly]

Wouldn't it be a good approach not to do anything with an input file, in case pairsamtools merge is provided with only a single file ?

• Right now it's up to distiller to check if it's a single-file input. Single files are treated differently - they're copied by distiller and are left untouched.

• pairsamtools merge however does something to the pairsam header, even if it's just a single file and there is nothing to merge. Modified headers cause downstream issues in case of hierarchical merge implemented in distiller. Dealing with that in pairsamtools merge would make distiller code cleaner.

[golobor]

done!