+ $(BADSIGMATCH) { \
+ s = $$13; \
+ for (i = length(s)/2; i >= 0; i--) { \
+ c = substr(s, i, 1); \
+ if (c != tolower(c)) { c = tolower(c); break; } \
+ else if (c != toupper(c)) { c = toupper(c); break; } \
+ } \
+ $$13 = substr(s, 0, i) c substr(s, i + 1); \
+ } \
+ { print; }' \