diff --git a/arch-chroot.in b/arch-chroot.in
index e85d7f3..de7b543 100644
--- a/arch-chroot.in
+++ b/arch-chroot.in
@@ -6,7 +6,7 @@ m4_include(common)
 
 usage() {
   cat <<EOF
-usage: ${0##*/} <chroot-dir>
+usage: ${0##*/} chroot-dir
 
 EOF
 }
diff --git a/genfstab.in b/genfstab.in
index eb6e642..2bc121c 100644
--- a/genfstab.in
+++ b/genfstab.in
@@ -39,14 +39,16 @@ root=/mnt
 
 usage() {
   cat <<EOF
-usage: ${0##*/} [options]
+usage: ${0##*/} root [options]
 
   Options:
     -L             Use labels for source identifiers
     -p             Avoid printing pseudofs mounts
-    -r root        Generate based on 'root' (default: /mnt)
     -U             Use UUIDs for source identifiers
 
+genfstab generates output suitable for addition to an fstab file based on the
+devices mounted under the mountpoint specified by the given root.
+
 EOF
 }
 
@@ -55,7 +57,7 @@ if [[ -z $1 || $1 = @(-h|--help) ]]; then
   exit $(( $# ? 0 : 1 ))
 fi
 
-while getopts ':Lpr:U' flag; do
+while getopts ':LpU' flag; do
   case $flag in
     L)
       bylabel=1
@@ -66,10 +68,6 @@ while getopts ':Lpr:U' flag; do
     p)
       nopseudofs=1
       ;;
-    r)
-      # trim trailing slashes
-      root=${OPTARG%%+(/)}
-      ;;
     :)
       die '%s: option requires an argument -- '\''%s'\' "${0##*/}" "$OPTARG"
       ;;
@@ -80,6 +78,13 @@ while getopts ':Lpr:U' flag; do
 done
 shift $(( OPTIND - 1 ))
 
+(( $# )) || die "No root directory specified"
+root=${1%%+(/)}; shift
+
+if ! mountpoint -q "$root"; then
+  die "$root is not a mountpoint"
+fi
+
 if (( bylabel && byuuid )); then
   die "cannot specify both -U and -L"
 fi
diff --git a/pacstrap.in b/pacstrap.in
index 8670e83..d56b3e4 100644
--- a/pacstrap.in
+++ b/pacstrap.in
@@ -17,12 +17,14 @@ hostcache=0
 
 usage() {
   cat <<EOF
-usage: ${0##*/} [options]
+usage: ${0##*/} [options] root [packages...]
 
   Options:
-    -r root        Install to 'root' (default: /mnt)
-    -d             Allow installation to a non-mountpoint directory
     -c             Use the package cache on the host, rather than the target
+    -d             Allow installation to a non-mountpoint directory
+
+pacstrap installs packages to the specified new root directory. If no packages
+are given, pacstrap defaults to the "base" group.
 
 EOF
 }
@@ -34,14 +36,11 @@ fi
 
 (( EUID == 0 )) || die 'This script must be run with root privileges'
 
-while getopts ':cdr:' flag; do
+while getopts ':cd' flag; do
   case $flag in
     d)
       directory=1
       ;;
-    r)
-      newroot=$OPTARG
-      ;;
     c)
       hostcache=1
       ;;
@@ -55,11 +54,9 @@ while getopts ':cdr:' flag; do
 done
 shift $(( OPTIND - 1 ))
 
-if (( $# )); then
-  pacman_args=("$@")
-else
-  pacman_args=('base' 'base-devel')
-fi
+(( $# )) || die "No root directory specified"
+newroot=$1; shift
+pacman_args=("${@:-base}")
 
 if (( ! hostcache )); then
   pacman_args+=(--cachedir="$newroot/var/cache/pacman/pkg")