Extract a common expression into a variable/const.

This is Refactoring / code cleanup.

See:

* https://refactoring.com/catalog/extractMethod.html

* https://en.wikipedia.org/wiki/Code_refactoring

* https://www.refactoring.com/

* https://www.joelonsoftware.com/2002/01/23/rub-a-dub-dub/

Some small optimisations may have slipped in as well.

Author: shlomif

fortune-mod/datfiles/data/rules-of-acquisition-gen.sh

@@ -26,9 +26,10 @@ then
 	exit 2
 fi
 
+format="${title_template}\\n${rule_template}\\n${source_template}\\n${footer_template}\\n"
+
 # Convert CSV to DAT + wrap long lines + remove trailing whitespace
 while IFS="${csv_delimiter}" read -r number rule source
 do
-	printf -- "${title_template}\\n${rule_template}\\n${source_template}\\n${footer_template}\\n" \
-        "${number}" "${rule}" "${source}"
+	printf -- "${format}" "${number}" "${rule}" "${source}"
 done < "${infile}" | fold -sw "${line_maxlen}" | sed -e 's/[[:space:]]*$//' > "${outfile}"