diff --git a/xCAT/postscripts/ospkgs b/xCAT/postscripts/ospkgs
index e50b3c4da..20ece81c6 100755
--- a/xCAT/postscripts/ospkgs
+++ b/xCAT/postscripts/ospkgs
@@ -261,24 +261,6 @@ array_ospkgdirs=($OSPKGDIR)
 
 array_empty os_path
 
-is_el_modular_pkgdir()
-{
-    pmatch "$OSVER" "rhel[89]*" ||
-    pmatch "$OSVER" "rhel1[0-9]*" ||
-    pmatch "$OSVER" "rhels[89]*" ||
-    pmatch "$OSVER" "rhels1[0-9]*" ||
-    pmatch "$OSVER" "centos[89]*" ||
-    pmatch "$OSVER" "centos1[0-9]*" ||
-    pmatch "$OSVER" "rocky[89]*" ||
-    pmatch "$OSVER" "rocky1[0-9]*" ||
-    pmatch "$OSVER" "alma[89]*" ||
-    pmatch "$OSVER" "alma1[0-9]*" ||
-    pmatch "$OSVER" "almalinux[89]*" ||
-    pmatch "$OSVER" "almalinux1[0-9]*" ||
-    pmatch "$OSVER" "ol[89]*" ||
-    pmatch "$OSVER" "ol1[0-9]*"
-}
-
 index=0
 for dir in  ${array_ospkgdirs[@]}
 do
@@ -308,7 +290,7 @@ do
             ospkgdir="$ospkgdir/SL"
         fi
     fi
-    if ! is_el_modular_pkgdir || \
+    if ! xcat_is_el_modular_pkgdir "$OSVER" || \
        { [ "$dir" != "$default_pkgdir" ] && [ "$dir" != "$default_pkgdir/" ]; }; then
         # For EL8+ modular distros, only the base OS pkgdir expands to subrepos.
         array_set_element os_path $index $ospkgdir
@@ -376,7 +358,7 @@ do
                          array_set_element os_path $index $ospkgdir_ok
                      done
                  fi   # x86_64
-            elif is_el_modular_pkgdir; then
+            elif xcat_is_el_modular_pkgdir "$OSVER"; then
                  # for EL8+ modular distros the repodata is in ./BaseOS and ./AppStream, not in ./
                  for arg in "BaseOS" "AppStream"
                  do
diff --git a/xCAT/postscripts/otherpkgs b/xCAT/postscripts/otherpkgs
index 6dbc9707a..8815e69ca 100755
--- a/xCAT/postscripts/otherpkgs
+++ b/xCAT/postscripts/otherpkgs
@@ -341,24 +341,6 @@ fi
     IFS=$OIFS
     array_empty os_path
 
-    is_el_modular_pkgdir()
-    {
-        pmatch "$OSVER" "rhel[89]*" ||
-        pmatch "$OSVER" "rhel1[0-9]*" ||
-        pmatch "$OSVER" "rhels[89]*" ||
-        pmatch "$OSVER" "rhels1[0-9]*" ||
-        pmatch "$OSVER" "centos[89]*" ||
-        pmatch "$OSVER" "centos1[0-9]*" ||
-        pmatch "$OSVER" "rocky[89]*" ||
-        pmatch "$OSVER" "rocky1[0-9]*" ||
-        pmatch "$OSVER" "alma[89]*" ||
-        pmatch "$OSVER" "alma1[0-9]*" ||
-        pmatch "$OSVER" "almalinux[89]*" ||
-        pmatch "$OSVER" "almalinux1[0-9]*" ||
-        pmatch "$OSVER" "ol[89]*" ||
-        pmatch "$OSVER" "ol1[0-9]*"
-    }
-
     is_el_yum_distro()
     {
         pmatch "$OSVER" "rhel*" ||
@@ -398,7 +380,7 @@ fi
                 ospkgdir="$ospkgdir/SL"
             fi
         fi
-        if ! is_el_modular_pkgdir || \
+        if ! xcat_is_el_modular_pkgdir "$OSVER" || \
            { [ "$dir" != "$default_pkgdir" ] && [ "$dir" != "$default_pkgdir/" ]; }; then
         # For EL8+ modular distros, only the base OS pkgdir expands to subrepos.
             array_set_element os_path $index $ospkgdir
@@ -441,7 +423,7 @@ fi
                              array_set_element os_path $index $ospkgdir_ok
                          done
                      fi   # x86_64
-                elif is_el_modular_pkgdir; then
+                elif xcat_is_el_modular_pkgdir "$OSVER"; then
                      # for EL8+ modular distros the repodata is in ./BaseOS and ./AppStream, not in ./
                      for arg in "BaseOS" "AppStream"
                      do
diff --git a/xCAT/postscripts/xcatpkgutils.sh b/xCAT/postscripts/xcatpkgutils.sh
index 8c91b5239..857b1b586 100755
--- a/xCAT/postscripts/xcatpkgutils.sh
+++ b/xCAT/postscripts/xcatpkgutils.sh
@@ -3,5 +3,20 @@
 
 # Shared POSIX shell helpers for the ospkgs and otherpkgs postscripts.
 # Keep the marker assignment last so callers know the whole library loaded.
+
+xcat_is_el_modular_pkgdir()
+{
+    case "$1" in
+        rhel[89]*|rhel1[0-9]*|rhels[89]*|rhels1[0-9]*|\
+        centos[89]*|centos1[0-9]*|rocky[89]*|rocky1[0-9]*|\
+        alma[89]*|alma1[0-9]*|almalinux[89]*|almalinux1[0-9]*|\
+        ol[89]*|ol1[0-9]*)
+            return 0
+            ;;
+    esac
+
+    return 1
+}
+
 # shellcheck disable=SC2034
 XCATPKGUTILS_LOADED=1