'getpkgs' installs packages from package lists assigned to a SRC in a src file. The default being /etc/pkg-tools/RC. However there are no pakcages lists assigned by default. And is not recommended adding them in the system RC file.

'getpkgs' is not really meant to be a general purpose user command. But instead a building block for an installer.

getpkgs is more sophisticated than getpkg. It will update its database automatically. There is no need to run pkg-u first. An example is as follows...

mntpt=$(pwd)/work CACHE=/tmp/distorcache  PKG_LST_DIR=$(pwd)/pkgslists RC_FILE=$(pwd)/Bob.rc getpkgs

Where the RC_FILE of Bob.rc has in it...

RSYNC:slackware.uk/people/alien/restricted_sbrepos/14.2/x86_64:alienbob_uk_restricted

Checkout SOURCE for a breakdown of this source line.
And the pkgslist file of $(pwd)/pkgslists/alienbob_uk_restricted.pkgs looks like...

multimedia/vlc2

It could also look like...

vlc2

The first method of using a location subdirectory is most useful with official Slackware repositories to maintain proper installation order. It is the default for SlackBuilder xxx.pkgs files. However in order to accomodate liveslack's pkgslist.lst format a simple one column package name list is also valid. You just need to take pains to insure the correct installation order.

Note: This is a simple yet powerful mechanism to integrate a network savy package manager into other projects. ie: liveslack.
I have completed connecting Eric's livelsack scripts with the Slackbuilder installer for 14.2. It will be a choice available under the Settings Tab. However, I have not shipped this option to the public yet.