Fix unbound variable errors

seqs/backup.sh

@@ -54,21 +54,21 @@ step_3_info() {
   local tar="<TARGET>"
   local exc="[EXCLUDES...]"
   shift
-  if [ "$1" == "-t" ] ; then
+  if [ "${1:-}" == "-t" ] ; then
     opt=" -t     "
     tar=
     shift
   fi
-  if [ ! -z "$1" ] ; then
+  if [ -n "${1:-}" ] ; then
     dir="$1"
     shift
-    if [ ! -z $tar ] && [ ! -z "$1" ] ; then
+    if [ -n $tar ] && [ -n "$1" ] ; then
       tar="$1"
       shift
     else
       tar="$BACKUP_TARGET"
     fi
-    if [ ! -z "$1" ] ; then
+    if [ -n "${1:-}" ] ; then
       exc="$@"
     else
       exc="[NO EXCLUDES]"
@@ -83,7 +83,6 @@ step_3_info() {
 }
 step_3_alias() { echo "budir"; }
 step_3() {
-  local arg
   local configTarget=0
   local noRemount=0
   local buSource=
@@ -93,7 +92,7 @@ step_3() {
   # don't use step number
   shift
 
-  for arg in "$@"; do
+  for _ in "$@"; do
     case "$1" in
       -t)
         configTarget=1