usage information updated to reflect the new way to pass options to Redis from the command line.

src/redis.c

@@ -1856,8 +1856,16 @@ void version() {
 }
 
 void usage() {
-    fprintf(stderr,"Usage: ./redis-server [/path/to/redis.conf]\n");
+    fprintf(stderr,"Usage: ./redis-server [/path/to/redis.conf] [options]\n");
     fprintf(stderr,"       ./redis-server - (read config from stdin)\n");
+    fprintf(stderr,"       ./redis-server -v or --version\n");
+    fprintf(stderr,"       ./redis-server -h or --help\n\n");
+    fprintf(stderr,"Examples:\n");
+    fprintf(stderr,"       ./redis-server (run the server with default conf)\n");
+    fprintf(stderr,"       ./redis-server /etc/redis/6379.conf\n");
+    fprintf(stderr,"       ./redis-server --port 7777\n");
+    fprintf(stderr,"       ./redis-server --port 7777 --slaveof 127.0.0.1 8888\n");
+    fprintf(stderr,"       ./redis-server /etc/myredis.conf --loglevel verbose\n");
     exit(1);
 }