shell/ not bash/

shell/rename.awk

@@ -0,0 +1,27 @@
+# generates a string of "oldname newname" from 2 records, for use with mv. Main
+# problem solved here generating the newname string using the number prefix and
+# filetype affix.
+
+BEGIN {
+  FS="."
+  oldname = ""
+  num = ""
+  ext = ""
+  newname = ""
+}
+
+NR == 1 {
+  oldname = $0
+  num = $1
+  # important that this is the last field, not numbered, to allow for a file
+  # without a string descriptor.
+  ext = $NF
+}
+
+NR == 2 {
+  newname = sprintf("%s.%s.%s", num, $0, ext)
+}
+
+END {
+  print oldname, newname
+}