Applied patch from I.Q. to add sort -u as a feature.

Config.h

@@ -235,9 +235,12 @@
 // Enable support for tar -z option (currently only works for inflating)
 #define BB_FEATURE_TAR_GZIP 
 //
-//// Enable reverse sort
+// Enable reverse sort
 #define BB_FEATURE_SORT_REVERSE
 //
+// Enable uniqe sort
+#define BB_FEATURE_SORT_UNIQUE
+//
 // Enable command line editing in the shell.  
 // Only relevant if BB_SH is enabled. On by default.
 #define BB_FEATURE_COMMAND_EDITING

applets/usage.h

@@ -1356,15 +1356,24 @@
 	"[2 second delay results]\n"
 
 
+#ifdef BB_FEATURE_SORT_UNIQUE
+  #define USAGE_SORT_UNIQUE(a) a
+#else
+  #define USAGE_SORT_UNIQUE(a)
+#endif
 #ifdef BB_FEATURE_SORT_REVERSE
   #define USAGE_SORT_REVERSE(a) a
 #else
   #define USAGE_SORT_REVERSE(a)
 #endif
 #define sort_trivial_usage \
-	"[-n]" USAGE_SORT_REVERSE(" [-r]") " [FILE]..."
+	"[-n" USAGE_SORT_REVERSE("r") USAGE_SORT_UNIQUE("u") "] [FILE]..."
 #define sort_full_usage \
-	"Sorts lines of text in the specified files"
+	"Sorts lines of text in the specified files\n\n"\
+	"Options:\n" \
+	USAGE_SORT_UNIQUE("\t-u\tsuppress duplicate lines\n") \
+	USAGE_SORT_REVERSE("\t-r\tsort in reverse order\n") \
+	"\t-n\tsort numerics"
 #define sort_example_usage \
 	"$ echo -e \"e\\nf\\nb\\nd\\nc\\na\" | sort\n" \
 	"a\n" \

coreutils/sort.c

@@ -46,8 +46,11 @@ int sort_main(int argc, char **argv)
 #ifdef BB_FEATURE_SORT_REVERSE
 	int reverse = FALSE;
 #endif
+#ifdef BB_FEATURE_SORT_UNIQUE
+	int unique = FALSE;
+#endif
 
-	while ((opt = getopt(argc, argv, "nr")) != -1) {
+	while ((opt = getopt(argc, argv, "nru")) != -1) {
 		switch (opt) {
 			case 'n':
 				compare = compare_numeric;
@@ -56,6 +59,11 @@ int sort_main(int argc, char **argv)
 			case 'r':
 				reverse = TRUE;
 				break;
+#endif
+#ifdef BB_FEATURE_SORT_UNIQUE
+			case 'u':
+				unique = TRUE;
+				break;
 #endif
 			default:
 				show_usage();
@@ -81,12 +89,18 @@ int sort_main(int argc, char **argv)
 
 	/* print it */
 #ifdef BB_FEATURE_SORT_REVERSE
-	if (reverse)
+	if (reverse) {
-		for (i = nlines - 1; 0 <= i; i--)
+		for (i = --nlines; 0 <= i; i--)
-			puts(lines[i]);
+#ifdef BB_FEATURE_SORT_UNIQUE
-	else
+			if((!unique) || (i == nlines) || (strcmp(lines[i + 1], lines[i])))
 #endif
-	for (i = 0; i < nlines; i++)
+				puts(lines[i]);
-		puts(lines[i]);
+	} else
+#endif
+		for (i = 0; i < nlines; i++)
+#ifdef BB_FEATURE_SORT_UNIQUE
+			if((!unique) || (!i) || (strcmp(lines[i - 1], lines[i])))
+#endif
+				puts(lines[i]);
 	return EXIT_SUCCESS;
 }

include/usage.h

@@ -1356,15 +1356,24 @@
 	"[2 second delay results]\n"
 
 
+#ifdef BB_FEATURE_SORT_UNIQUE
+  #define USAGE_SORT_UNIQUE(a) a
+#else
+  #define USAGE_SORT_UNIQUE(a)
+#endif
 #ifdef BB_FEATURE_SORT_REVERSE
   #define USAGE_SORT_REVERSE(a) a
 #else
   #define USAGE_SORT_REVERSE(a)
 #endif
 #define sort_trivial_usage \
-	"[-n]" USAGE_SORT_REVERSE(" [-r]") " [FILE]..."
+	"[-n" USAGE_SORT_REVERSE("r") USAGE_SORT_UNIQUE("u") "] [FILE]..."
 #define sort_full_usage \
-	"Sorts lines of text in the specified files"
+	"Sorts lines of text in the specified files\n\n"\
+	"Options:\n" \
+	USAGE_SORT_UNIQUE("\t-u\tsuppress duplicate lines\n") \
+	USAGE_SORT_REVERSE("\t-r\tsort in reverse order\n") \
+	"\t-n\tsort numerics"
 #define sort_example_usage \
 	"$ echo -e \"e\\nf\\nb\\nd\\nc\\na\" | sort\n" \
 	"a\n" \

sort.c

@@ -46,8 +46,11 @@ int sort_main(int argc, char **argv)
 #ifdef BB_FEATURE_SORT_REVERSE
 	int reverse = FALSE;
 #endif
+#ifdef BB_FEATURE_SORT_UNIQUE
+	int unique = FALSE;
+#endif
 
-	while ((opt = getopt(argc, argv, "nr")) != -1) {
+	while ((opt = getopt(argc, argv, "nru")) != -1) {
 		switch (opt) {
 			case 'n':
 				compare = compare_numeric;
@@ -56,6 +59,11 @@ int sort_main(int argc, char **argv)
 			case 'r':
 				reverse = TRUE;
 				break;
+#endif
+#ifdef BB_FEATURE_SORT_UNIQUE
+			case 'u':
+				unique = TRUE;
+				break;
 #endif
 			default:
 				show_usage();
@@ -81,12 +89,18 @@ int sort_main(int argc, char **argv)
 
 	/* print it */
 #ifdef BB_FEATURE_SORT_REVERSE
-	if (reverse)
+	if (reverse) {
-		for (i = nlines - 1; 0 <= i; i--)
+		for (i = --nlines; 0 <= i; i--)
-			puts(lines[i]);
+#ifdef BB_FEATURE_SORT_UNIQUE
-	else
+			if((!unique) || (i == nlines) || (strcmp(lines[i + 1], lines[i])))
 #endif
-	for (i = 0; i < nlines; i++)
+				puts(lines[i]);
-		puts(lines[i]);
+	} else
+#endif
+		for (i = 0; i < nlines; i++)
+#ifdef BB_FEATURE_SORT_UNIQUE
+			if((!unique) || (!i) || (strcmp(lines[i - 1], lines[i])))
+#endif
+				puts(lines[i]);
 	return EXIT_SUCCESS;
 }

usage.h

@@ -1356,15 +1356,24 @@
 	"[2 second delay results]\n"
 
 
+#ifdef BB_FEATURE_SORT_UNIQUE
+  #define USAGE_SORT_UNIQUE(a) a
+#else
+  #define USAGE_SORT_UNIQUE(a)
+#endif
 #ifdef BB_FEATURE_SORT_REVERSE
   #define USAGE_SORT_REVERSE(a) a
 #else
   #define USAGE_SORT_REVERSE(a)
 #endif
 #define sort_trivial_usage \
-	"[-n]" USAGE_SORT_REVERSE(" [-r]") " [FILE]..."
+	"[-n" USAGE_SORT_REVERSE("r") USAGE_SORT_UNIQUE("u") "] [FILE]..."
 #define sort_full_usage \
-	"Sorts lines of text in the specified files"
+	"Sorts lines of text in the specified files\n\n"\
+	"Options:\n" \
+	USAGE_SORT_UNIQUE("\t-u\tsuppress duplicate lines\n") \
+	USAGE_SORT_REVERSE("\t-r\tsort in reverse order\n") \
+	"\t-n\tsort numerics"
 #define sort_example_usage \
 	"$ echo -e \"e\\nf\\nb\\nd\\nc\\na\" | sort\n" \
 	"a\n" \