Patch from Matt Kraai to implement uniq -[cdu]
diff --git a/applets/usage.c b/applets/usage.c
index 75c421a..ae6cec8 100644
--- a/applets/usage.c
+++ b/applets/usage.c
@@ -1365,6 +1365,10 @@
#ifndef BB_FEATURE_TRIVIAL_HELP
"\nDiscard all but one of successive identical lines from INPUT\n"
"(or standard input), writing to OUTPUT (or standard output).\n"
+ "Options:\n"
+ "\t-c\tprefix lines by the number of occurrences\n"
+ "\t-d\tonly print duplicate lines\n"
+ "\t-u\tonly print unique lines\n"
#endif
;
#endif