added list "installed" functionality

pman.sh

@@ -29,6 +29,15 @@ fi
 # Evaluate the command arguments
 if [ "$command_args" = "search" ]; then
   command_args="-Ss"
+elif [ "$command_args" = "provides" ]; then
+  command_args="-F"
+elif [ "$command_args" = "installed" ]; then
+  command_args="-Q"
+elif [ "$command_args" = "install" ]; then
+  command_args="-S"
+  if [ "$command" = "pacman" ]; then
+    su_needed=true
+  fi
 elif [ "$command_args" = "update" ]; then
   command_args="-Sy"
   if [ "$command" = "pacman" ]; then
@@ -41,11 +50,6 @@ elif [ "$command_args" = "upgrade" ]; then
   if [ "$command" = "pacman" ]; then
     su_needed=true
   fi
-elif [ "$command_args" = "install" ]; then
-  command_args="-S"
-  if [ "$command" = "pacman" ]; then
-    su_needed=true
-  fi
 elif [ "$command_args" = "remove" ]; then
   command_args="-Rs"
   if [ "$command" = "pacman" ]; then
@@ -56,8 +60,6 @@ elif [ "$command_args" = "purge" ]; then
   if [ "$command" = "pacman" ]; then
     su_needed=true
   fi
-elif [ "$command_args" = "provides" ]; then
-  command_args="-F"
 elif [ "$more_arguments" = "true" ]; then
   echo "Invalid command: \"$command $command_args\""
   echo
@@ -67,20 +69,26 @@ elif [ "$more_arguments" = "true" ]; then
   echo "               (aur packages - all the normal operations except config are available)"
   echo "  aur (yay)  - yay              | same as \"yay\""
   echo "  search     - pacman -Ss       | search packages"
+  echo "  provides   - pacman -F        | list packages that provide file"
+  echo "  installed  - pacman -Q        | list installed packages"
   echo "  install    - pacman -S        | install packages"
   echo "  update     - pacman -Sy       | updates the repositories"
   echo "  upgradable - pacman -Qu       | list available upgrades"
   echo "  upgrade    - pacman -Syu      | upgrades your system"
-  echo "  provides   - pacman -F        | list packages that provide file"
   echo "  remove     - pacman -Rs       | remove packages & dependencies"
   echo "  purge      - pacman -Rns      | remove packages, dependencies & conf"
   echo "  config     - /etc/pacman.conf | edits pacman configuration"
   exit 1
 fi
 
-# If sudo is needed and necessary (and installed), prepend it
-if [ "$su_needed" = "true" ] && [ "$UID" != 0 ] && command -v "sudo" &>/dev/null; then
-  sudo $command $command_args "${@}"
+# If sudo is needed and necessary (and installed), prepend it, if not installed throw error
+if [ "$su_needed" = "true" ] && [ "$UID" != 0 ]; then
+  if command -v "sudo" &>/dev/null; then
+    sudo $command $command_args "${@}"
+  else
+    echo "sudo command needed but not found" > /dev/stderr
+    exit 1
+  fi
 else
   $command $command_args "${@}"
 fi