diff --git a/functions.sh b/functions.sh
index a7adec2..bc95e68 100755
--- a/functions.sh
+++ b/functions.sh
@@ -8,49 +8,55 @@ mkcd() { mkdir $1 && cd $1 }
 rcd() { cd .. && rm -irfv $OLDPWD }
 
 extract () {
- if [ -f $1 ] ; then
- case $1 in
- *.tar.bz2)   tar xjf $1        ;;
- *.tar.gz)    tar xzf $1     ;;
- *.tar.xz)    tar xJf $1     ;;
- *.bz2)       bunzip2 $1       ;;
- *.lbz2)      lbunzip2 -kn$((`grep "^processor" /proc/cpuinfo | wc -l`+1)) $1 ;;
- *.rar)       unrar x $1     ;;
- *.gz)        gunzip $1     ;;
- *.tar)       tar xf $1        ;;
- *.tbz2)      tar xjf $1      ;;
- *.tbz)       tar -xjvf $1    ;;
- *.tgz)       tar xzf $1       ;;
- *.txz)       tar xJf $1       ;;
- *.zip)       unzip $1     ;;
- *.Z)         uncompress $1  ;;
- *.7z)        7z x $1    ;;
- *)           echo "I don't know how to extract '$1'..." ;;
- esac
- else
- echo "'$1' is not a valid file"
- fi
+  if [ $2 ] ; then
+    echo "too many parameters to extract ()"
+  elif [ -f "$1" ] ; then
+    case $1 in
+    *.tar.bz2|*.tbz2|*.tbz)   tar xjf $1 ;; # FIXME: make parallel with lbunzip2
+    *.tar.gz|*.tgz)           tar xzf $1 ;;
+    *.tar.xz|*.txz)           tar xJf $1 ;;
+    *.tar)                    tar xf $1 ;;
+    *.bz2)                    which lbunzip2 &>/dev/null \
+                                && lbunzip2 -kn$((`grep "^processor" /proc/cpuinfo -c`+1)) $1 \
+                                || bunzip2 -c $1 > ${1%.bz2} ;;
+    *.gz)                     gunzip -c $1 > ${1%.gz} ;;
+    *.xz)                     unxz -c $1 > ${1%.xz} ;;
+    *.rar)                    unrar x $1 ;; # FIXME: test
+    *.zip)                    unzip $1 ;;
+    *.Z)                      uncompress $1 ;; # FIXME: test
+    *.7z)                     7z x $1 ;;
+    *)                        echo "I don't know how to extract '$1'..." ;;
+    esac
+  else
+    echo "'$1' is not a valid file"
+    echo "Usage: extract file"
+  fi
 } 
 
 
 pk () {
- if [ $1 ] ; then
- case $1 in
- tbz)       tar cjvf $2.tar.bz2 $2      ;;
- tgz)       tar czvf $2.tar.gz  $2       ;;
- tgz)       tar cJvf $2.tar.xz  $2       ;;
- tar)       tar cpvf $2.tar  $2       ;;
- bz2)       bzip2 $2 ;;
- lbz2)      lbzip2 -kn$((`grep "^processor" /proc/cpuinfo | wc -l`+1)) $2 ;;
- gz)        gzip -c -9 -n $2 > $2.gz ;;
- xz)        xz -c -9 $2 > $2.xz ;;
- zip)       zip -r $2.zip $2   ;;
- 7z)        7z a $2.7z $2    ;;
- *)         echo "'$1' cannot be packed via pk()" ;;
- esac
- else
- echo "'$1' is not a valid file"
- fi
+  if [ $3 ] ; then
+    echo "too many parameters to pk ()"
+  elif [ $1 ] ; then
+    case $1 in
+      t*b*z*)         tar cjvf $2.tar.bz2 $2 ;; # FIXME: make parallel with lbzip2
+      t*g*z)          tar czvf $2.tar.gz  $2 ;;
+      t*x*|t*J*)      tar cJvf $2.tar.xz  $2 ;;
+      t*r)            tar cpvf $2.tar  $2 ;;
+      b*z*)           which lbzip2 &>/dev/null \
+                        && lbzip2 -9 -kn$((`grep "^processor" /proc/cpuinfo -c`+1)) $2 \
+                        || bzip2 -9 -c $2 > $2.bz2 ;;
+      g*z)            gzip -c -9 -n $2 > $2.gz ;;
+      x*z)            xz -c -9 $2 > $2.xz ;;
+      rar)            ;; # FIXME: test
+      zip)            zip -9 -r $2.zip $2 ;;
+      Z)              ;; # FIXME: test
+      7z)             7z -mx=9 a $2.7z $2 ;;
+      *)              echo "'$1' cannot be packed via pk()" ;;
+    esac
+  else
+    echo "Usage: pk tbz file"
+  fi
 } 
 
 calc() {