slackpkg install slacky:openjdk => register=(slacky:openjdk)+register
slackpkg install slackware:mozilla-firefox => register=(slackware:mozilla-firefox)+register
...

slackpkg upgrade-all => 
  PKGS_PRIORITY="slackware:mozilla-firefox slacky:openjdk "+PKGS_PRIORITY 
  upgrade-all

slackpkg upgrade alienbob:openjdk => 
  :register=(alienbob:openjdk)+register
  :PKGS_PRIORITY="alienbob:openjdk slackware:mozilla-firefox slacky:openjdk "+PKGS_PRIORITY
  :upgrade

    sed -i -r -e '1,/^#PKGS_PRIORITY=.*$/s/^(#PKGS_PRIORITY=.*)$/\1\nPKGS_PRIORITY=( multilib: )\n/' $CONF/slackpkgplus.conf

--- slackpkgplus.sh.orig        2015-11-20 16:34:54.633426641 +0100
+++ slackpkgplus.sh     2015-11-20 16:35:45.887428928 +0100
@@ -579,6 +579,12 @@
     done
   } # END searchlistEX()
 
+       # Ensure each repository url has a trailing slash...
+       #
+  for PREPO in "${!MIRRORPLUS[@]}" ; do
+       MIRRORPLUS[$PREPO]="${MIRRORPLUS[$PREPO]%/}/"
+  done
+
   touch $TMPDIR/greylist.1
   if [ -e $CONF/greylist ];then
     cat $CONF/greylist|sed -e 's/#.*//'|grep -v -e '^#' -e '^$'|awk '{print $1}'|sort -u >$TMPDIR/greylist.1

-+       MIRRORPLUS[$PREPO]="${MIRRORPLUS[$PREPO]/}/"
++       MIRRORPLUS[$PREPO]="${MIRRORPLUS[$PREPO]%/}/"

--- slackpkgplus.sh.orig        2015-11-21 12:59:57.349236501 +0100
+++ slackpkgplus.sh     2015-11-21 13:01:12.379239849 +0100
@@ -408,13 +408,11 @@
         # ARGUMENT is always a basename. But PAT can be:
         #   1. a regular expression (ie .*)
         #   2. a basename (openjdk)
-        #   3. a partial (or complete) package name (vlc-2.0.6, ).
         #
-        # The current "enhanced priority rule" is applied :
-        #   + In case (1) and (2) when ARGUMENT contains the pattern PAT
-        #   + In the case (3) when ARGUMENT starts the pattern PAT.
+        # The current "enhanced priority rule" is applied in case (1) 
+       # and (2) when ARGUMENT contains the pattern PAT
         #
-        if echo "$ARGUMENT" | grep -q "$PAT" || echo "$PAT" | grep "^$ARGUMENT" ; then
+        if echo "$ARGUMENT" | grep -q "$PAT" ; then
           PKGDATA=""
           PKGINFOS=$(grep -n -m 1 "^${DIR} ${ARGUMENT} " ${TMPDIR}/pkglist)

$slackpkg search phonon-gstreamer

DONE

The list below shows all packages with name matching "phonon-gstreamer".

[ Status           ] [ Repository               ] [ Package                                  ]
   installed                                        phonon-gstreamer-4.6.3-x86_64-1           
  upgrade              ktown                        phonon-gstreamer-4.6.3-x86_64-1 --> phonon-gstreamer-4.8.0-x86_64-1alien

$slackpkg upgrade-all

Checking local integrity... DONE
Looking for packages to upgrade. Please wait... DONE

No packages match the pattern for upgrade. Try:

        /usr/sbin/slackpkg install|reinstall

# Configuration for slackpkg+. See /usr/doc/slackpkg+-*/README for more details

# Enable (on) / Disable (off) slackpkg+
SLACKPKGPLUS=on

# set to '0' to never show the download progress bar
# set to '1' to show the bar only in download packages (default)
# set to '2' to always show the download bar
# set to '3' for a debug mode
VERBOSE=1

# By default slackpkg+ deny to install 32bit packages.
#
# Set this flag to 'on' allow slackpkg+ to install 32bit packages on a 64bit slackware 
# installation (possibly unsafe). Please, do not install both 32 and 64bit of the same 
# package to avoid problems, and NEVER upgrade existant 64bit packages with relative 32bit package.
# Do not forget to install the multilibs.
ALLOW32BIT=off

# Enable (1) / Disable (0) the official slackpkg blacklist. May be useful to temporarily skip
# the slackware blacklist. You can also override it from command line:
# 'USEBL=0 slackpkg upgrade-all'
USEBL=1

# Add custom option to 'wget'.
# You can solve the repository indisponibility issue by set a timeout here
WGETOPTS="--timeout=20 --tries=2"

# If you want replace wget with another downloader search DOWNLOADCMD in documentation
# at /usr/doc/slackpkg+-*/README
#DOWNLOADCMD="wget -O"

# Enable (on) / Disable (off) notification events (see notifymsg.conf)
#ENABLENOTIFY=off

# Enable (on) / Disable (off) the greylist feature. See /etc/slackpkg/greylist
GREYLIST=on

# If two or more repositories contains some same packages, you can specify
# from which repository you prefer to search it.
# The syntax is "<repository_name>:<package_name>"
# Accepts regular expressions. To give priority to an entire repository use "<repository_name>"

# Examples:
#PKGS_PRIORITY=( restricted:vlc )
# OR
#PKGS_PRIORITY=( myrepo )
# 
# if you have two reporitories to give priority you must set both in the same line
#PKGS_PRIORITY=( myrepo restricted:vlc )
#
# if you want to install 'ktown' repository you must set it here
#PKGS_PRIORITY=( ktown )
# and DO NOT MISS to read special instruction on /usr/doc/slackpkg+-*/repositories.txt
#
# If you want a multilib system, uncomment the multilib repository and set:
#PKGS_PRIORITY=( multilib )
#
# (Use /usr/doc/slackpkg+-*/setupmultilib.sh to setup a multilib configuration)
#
# For both multilib and ktown set
PKGS_PRIORITY=( patches:.* slackpkgplus:.* alienbob:flashplayer-plugin alienbob:libreoffice ktown:.* mled:.* )

# Otherwise you can try to upgrade a package from a repository that contains a package with the
# same tag of the already installed package. Tipically that means to upgrade a package from the
# same author of the already installed package.
# Note that this method may not works properly where two repositories contains a package with the
# same tag.
# Set TAG_PRIORITY to 'on' to enable this function
TAG_PRIORITY=off

# List repositories you want to use (defined below)
# remember to launch 'slackpkg update' if you modify that row.
REPOPLUS=( slackpkgplus ktown mled extras alienbob )

# Define mirrors (uncomment one or more mirror; remember to add it to REPOPLUS)
# GPG Note: after adding a repository, you must to run 'slackpkg update gpg'
#           some repositories as salixos or slackel, have a partial GPG support;
#           for that repositories you may need to run slackpkg with 'slackpkg -checkgpg=off ...'

# Slackware 14.1 - x86_64
#MIRRORPLUS['multilib']=http://taper.alienbase.nl/mirrors/people/alien/multilib/14.1/
MIRRORPLUS['ktown']=http://taper.alienbase.nl/mirrors/alien-kde/14.1/latest/x86_64/
MIRRORPLUS['mled']=http://www.microlinux.fr/microlinux/desktop-14.1-64bit/
MIRRORPLUS['extras']=http://www.microlinux.fr/microlinux/extras-14.1-64bit/
MIRRORPLUS['alienbob']=http://taper.alienbase.nl/mirrors/people/alien/sbrepos/14.1/x86_64/

# use this to keep the slackpkg+ package updated
MIRRORPLUS['slackpkgplus']=http://slakfinder.org/slackpkg+/

# Slackware current - x86_64
#MIRRORPLUS['multilib']=http://taper.alienbase.nl/mirrors/people/alien/multilib/current/

# Local repository:
#MIRRORPLUS['alienbob']=file://repositories/alien/sbrepos/14.1/x86/
#
# Local packages (you do not need metadata nor 'slackpkg update' command):
#MIRRORPLUS['myrepo']=dir://repositories/mypackages/

if echo "$ARGUMENT | grep -q "$PAT" || echo "$PAT" | grep "^$ARGUMENT" ; then

ARGUMENT=glibc
PAT=glibc-solibs

$ echo "glibc" | grep "glibc-solibs" || echo "glibc-solibs" | grep "^glibc" 
glibc-solibs

--- slackpkgplus.sh_1.5.1       2015-11-22 18:55:43.383684886 +0100
+++ slackpkgplus.sh     2015-11-22 19:10:38.183498349 +0100
@@ -611,7 +611,7 @@
     ((INDEX++))
   done
 
-  REPOPLUS=$(echo "${REPOPLUS[*]} ${PURE_PKGSPRIORITY[*]} ${!MIRRORPLUS[*]}"|sed 's/ /\n/g'|sed 's/:.*//'|awk '{if(!a[$1]++)print $1}')
+  REPOPLUS=( $(echo "${REPOPLUS[*]} ${PURE_PKGSPRIORITY[*]} ${!MIRRORPLUS[*]}"|sed 's/ /\n/g'|sed 's/:.*//'|awk '{if(!a[$1]++)print $1}') )
   PRIORITY=( ${PRIORITY[*]} SLACKPKGPLUS_$(echo ${REPOPLUS[*]}|sed 's/ / SLACKPKGPLUS_/g') )
 
   # Test repositories

$ ls -1 /var/log/packages/phonon*