On Fri, Jan 1, 2016 at 1:45 PM, Leo Famulari <leo@famulari.name> wrote:

I did this:
$ apt-cache pkgnames | tr -d 'a-zA-Z0-9' | tr -d - | tr -d '\n'

The only remaining characters were '.' and '+'.

I did:
ls -1 /var/cache/apt/archive/ | tr -d 'a-zA-Z0-9' | tr -d - | tr -d '\n'
Got:  . + % ~ _

typical pkgnames, as seen in the file system:

Note pkgname:

package-name  _  upstreamversion - localversion _ otherstuff

version delimited by _
may have optional subversions split by -
(like when an upstream version is remade on hydra, but is only locally different somehow.)

For your comtemplation.

I believe on debian the : is used when the package starts a new numbering scheme, like when
they decide the old scheme was crazy.