Following commands are available in slackware to work with packages.
Install
installpkg packagename.tgz
Remove
removepkg packagename.tgz
Upgrade
upgradepkg packagename.tgz
makepkg (Creates a new Slackware compatible package.)
explodepkg packagename.tgz
(Extracts the contents of a Slackware compatible package to the current directory.)
rpm2targz packaganame.rpm
(Converts an RPM package to standard GNU tar + zip format [tar.gz])
rpm2tgz packaganame.rpm
(Converts an RPM (RedHat Package Manager) to a Slackware-compatible package [tgz])
pkgtool
package maintenance tool