allow between 0 and 3 dot-separated numbers in python versiono

Author: d-w-moore

irods/test/harness/most_recent_python.sh

@@ -7,13 +7,19 @@ usage() {
     exit 2
 }
 MAJOR_MINOR=$1
-if ! [[ $MAJOR_MINOR =~ [0-9]+\.[0-9]+ ]]; then
+if [ -z "${MAJOR_MINOR}" ]; then                      # allow blank specification: most recent overall
+    MAJOR_MINOR='[0-9]\+\.[0-9]\+'
+elif [[ $MAJOR_MINOR =~ ^[0-9]+$ ]]; then             # allow single integer, eg. 3 for most recent 3.y.z
+    MAJOR_MINOR+='\.[0-9]\+'
+elif [[ $MAJOR_MINOR =~ [0-9]+\.[0-9]+ ]]; then       # allow x.y form, will yield output of most recent x.y.z
+    MAJOR_MINOR=$(sed 's/\./\\./'<<<"${MAJOR_MINOR}") # insert backslash in front of "."
+elif ! [[ $MAJOR_MINOR =~ [0-9]+\\?.[0-9]+ ]]; then
     usage
 fi
 
 url='https://www.python.org/ftp/python/'
 
 # Fetch the directory listing, extract version numbers, sort them to find the largest numerically.
 curl --silent "$url"|\
-sed -n 's!.*href="\('${MAJOR_MINOR}'\.[0-9]\+\)/".*!\1!p'|sort -rV|\
+sed -n 's!.*href="\('"${MAJOR_MINOR}"'\.[0-9]\+\)/".*!\1!p'|sort -rV|\
 head -n 1