diff --git a/astronaut/astronaut b/astronaut/astronaut
index 9a36897..124b626 100755
--- a/astronaut/astronaut
+++ b/astronaut/astronaut
@@ -1,15 +1,37 @@
 #!/bin/sh -e
 
 # Configuration
+
+# Build/install-time directories
 dir_build="/tmp/astronaut/build"  # Temporary directory to build packages
 dir_source="/tmp/astronaut/source"  # Directory where the package sources will be placed
 dir_install="/tmp/astronaut/install"  # Directory where the package will be installed
+
+# Runtime directories
 dir_sysroot=""  # The root directory of the system
 dir_prefix="/usr"  # Prefix directory (for /bin, /lib, /share and such)
+
+# Default commands
 cmd_download="curl -# -L -o {dst} {src}"  # Command to execute to download files
 cmd_extract="tar -x -C {dst} -f {src}"  # Command to execute to extract files
-unset dir_satellites  # Directory where the satellite files are placed.
-unset options
+
+# If we can't find the satellite file,  we'll look in this directory for it.
+unset dir_satellites
+
+# Options are comma-separated and parsed from front to back.
+# This means that in "!opt,someotheropt,opt", opt is disabled.
+
+unset options  # The least-priority global options
+package_options() { :; }  # Per-package options function.
+# Example for package_options:
+# package_options() {
+#     case "$1" in
+#         package1) echo "opt1,opt2,opt3" ;;
+#         package2) echo "someotheropts" ;;
+#     esac
+# }
+
+# Load any user configuration
 [ -f /etc/astronaut.conf ] && . /etc/astronaut.conf
 [ -f "$HOME/.astronaut.conf" ] && . "$HOME/.astronaut.conf"
 
@@ -17,6 +39,7 @@ unset options
 _download_only=false
 _vcs_only=false
 vcs_compile=false
+unset _user_options  # Options specified in the command line get the highest priority
 #_nuke_dir_install (This can be set from wrappers)
 
 # Some printing functions
@@ -34,7 +57,14 @@ Usage: $0 [-sbipr <dir>] [-Id] [-o <options>] <satellite>
 -I   Nuke install directory before build [WARNING: You will not be prompted]
 -d   Only download package files
 -v   Only build vcs package if any updates have been made to it
--o   Set package options (comma-separated)"
+-o   Set package options (comma-separated)
+
+Tips:
+- Use \`head -n 32 $0 > astronaut.conf.example\` to generate a default configuration file.
+- Keep in mind that when specifying options on the command line in a string, the first always takes priority.
+    For example, in \"opt,someotheropt,!opt\", opt is enabled, due to it being the first occurrence.
+- If you have set \$dir_satellites in the config, you can omit the .sat suffix.
+"
 }
 
 _msg() {
@@ -78,7 +108,7 @@ while getopts "h?s:b:i:r:p:IcCdvo:" opt; do
             _vcs_only=true
             ;;
         o)
-            options="$options,$OPTARG"
+            _user_options="$OPTARG,$_user_options"
             ;;
     esac
 done
@@ -164,15 +194,19 @@ option() {
     local enabled=false
     local opt
     local IFS=','; for option in $options; do
+        local option_negate=false
         case "$option" in
             *=*)
                 local value="$(echo "$option" | cut -d '=' -f 2)"
                 local option="$(echo "$option" | cut -d '=' -f 1)"
                 ;;
+            !*)
+                local option="$(echo "$option" | cut -c 2-)"
+                local option_negate=true
         esac
 
         if [ "$option" = "$check" ]; then
-            local enabled=true
+            [ "$option_negate" = true ] && local enabled=false || local enabled=true
             break
         fi
     done
@@ -243,6 +277,9 @@ if [ ! -f "$_satellite" ]; then
     fi
 fi
 
+# Build the definitive options list
+options="$_user_options$(package_options "$_satname"),$options"
+
 # Create the directories
 if [ "$_download_only" = false ]; then
     # This variable can be set by a wrapper script in need to nuke the install dir.