70124b0bcc90d53de666f37cccd6b1a4356161de
hiram
  Thu Feb 2 12:45:54 2023 -0800
correctly check for an unbound variable no redmine

diff --git src/hg/utils/otto/genArk/updateHgcentral.sh src/hg/utils/otto/genArk/updateHgcentral.sh
index 6f0836a..95545e1 100755
--- src/hg/utils/otto/genArk/updateHgcentral.sh
+++ src/hg/utils/otto/genArk/updateHgcentral.sh
@@ -1,30 +1,40 @@
 #!/bin/bash
 
 # *** Do not edit this file outside of the source tree. ***
 # This file is from source tree:
 #     kent/src/hg/utils/otto/genArk/updatgeHgcentral.sh
 # called by otto cron job in /hive/data/inside/GenArk/
 # and using the helper script:
 #     kent/src/hg/utils/otto/genArk/genArkListToSql.pl
 
 # exit on any error
 set -beEu -o pipefail
 
-if [ "xxx$1" != "xxxmakeItSo" ]; then
+function usage() {
   printf "usage: ./updateCentral.sh makeItSo\n" 1>&2
   printf "updates hgcentral.genark with the latest hub list from hgdownload\n" 1>&2
+}
+
+# check for an 'unbound' variable safely
+if [ -z "${1+x}" ]; then
+  usage
+  exit 255
+fi
+# something is in $1, verify is is 'makeItSo'
+if [ "xxx$1" != "xxxmakeItSo" ]; then
+  usage
   exit 255
 fi
 
 cd /hive/data/inside/GenArk
 export DS=`date "+%F"`
 export YYYY=`date "+%Y"`
 export LC_NUMERIC=en_US
 export msgTo="hclawson@ucsc.edu"
 # export msgTo="hclawson@ucsc.edu,lrnassar@ucsc.edu"
 export msgFile="/tmp/ottoGenArk.$$.txt"
 
 ###########################################################################
 ### helper functions
 ###########################################################################