diff --git a/optipdf b/optipdf
index fc32636..4ef798c 100755
--- a/optipdf
+++ b/optipdf
@@ -42,6 +42,12 @@ KEEP_BACKUP_SUFFIX=
 FORCE_OVERWRITE=0
 ENCODE_THRU_WARNINGS=0
 
+TEMP_DIR=$(mktemp -d -t "${0##*/}.XXXXXX")
+cleanup() {
+    rm -fr -- "$TEMP_DIR"
+}
+trap 'cleanup' EXIT
+
 FILES=()
 NO_MORE_FLAGS=0
 for ARG; do
@@ -98,11 +104,9 @@ for ARG; do
     fi
 done
 
-TEMP_DIR=
-
 if [[ ${#FILES[@]} -eq 0 ]]; then
     USAGE >&2
-    exit 2
+    exit 1
 fi
 
 file_size() {
@@ -155,16 +159,6 @@ hr_size() (
     printf '%g %s\n' "$HR_VAL" "$HR_UNIT"
 )
 
-setup_tempdir() {
-    if [[ -z $TEMP_DIR ]]; then
-        TEMP_DIR=$(mktemp -d -t "${0##*/}.XXXXXX")
-        cleanup() {
-            rm -fr -- "$TEMP_DIR"
-        }
-        trap 'cleanup' EXIT
-    fi
-}
-
 # copies $2 over to $1 if $2 is smaller than $1
 use_smaller() {
     # if `$TEMP' isn't empty and it's of a smaller size than `$FILE',
@@ -256,8 +250,7 @@ fi
 ERRORS=0
 FREED_TOTAL=0
 for FILE in "${FILES[@]}"; do
-    setup_tempdir
-    TEMP=$(mktemp -p "$TEMP_DIR" 'file.XXXXXX')
+    TEMP=$(mktemp -p "$TEMP_DIR" -t 'file.XXXXXX')
     rm -f -- "$TEMP"
     BEGIN_FILESIZE=$(file_size "$FILE")