Você precisa informar aptitude
para não fazer nenhuma formatação de coluna especial.
--disable-columns
This option causes aptitude search and aptitude versions to output their results without any special formatting. In particular: normally aptitude will add whitespace or truncate search results in an attempt to fit its results into vertical “columns”. With this flag, each line will be formed by replacing any format escapes in the format string with the corresponding text; column widths will be ignored.
Então faça isso:
$ aptitude search '?virtual' --disable-columns|grep ^v |grep -v i386|sort|uniq
v a52dec -
v a52dec-dev -
v aac-tactics -
v aalib1 -
v aalib-bin -
v acl-dev -
v ada-compiler -
v aide-binary -
v alphy -
...