Back in February I was rescued by Magic Banana from a predicament wherein I
was failing to remove duplicate lines from a two-column list of hostnames and
their IPv4 addresses:
https://trisquel.info/en/forum/sort-and-uniq-fail-remove-all-duplicates-list-hostnames-and-their-ipv4-addresses
Now I'm faced with a similar, longer (~80,000 rows) list of all the hostnames
in a collection of address blocks, from which I'm trying to _remove_ all the
lines whose hostnames are _not_ repeated. That should yield a list of
hostnames that are repeated within the same address block or even across
different address blocks.
This would be easy if I could flag repeated strings in the first column and
then sort them (along with their associated IPv4 addresses in the second
column, which contains no duplicates) so that I can make a two-column list of
just the hostnames that have multiple IPv4 addresses.
OpenOffice Calc seems to have a way of flagging duplicate values in adjacent
cells in a column, but mine freezes so often that the exerimentation would
take too long.
Thanks,
George Langford
