Support part of bsd-style command-line usage

Changelog

@@ -1,3 +1,5 @@
+# v3.9:
+  * Support part of bsd-style command-line usage.
 # v3.8:
   * Support more platforms, currently supports: arm64, armv7, armhf, riscv64, i386, loong64, s390x, ppc64le and x86_64.
   * Improve rootless container support.

README.md

@@ -72,6 +72,8 @@ wget -q -O - https://ruri.nekofeng.com | bash -s -- -s
 This will automatically download ruri binary to `./ruri`.      
 # Usage:    
 See [USAGE](doc/USAGE.md) to explore all features of ruri.         
+# About command-line:
+BSD style usage is partially supported now, for example, you can use `-pW /root`, but `-W/root` is not allowed.      
 # WARNING:      
 > [!WARNING]
 > ruri should always be executed with root privileges(sudo), and do not set SUID or any capability on it!      

src/info.c

@@ -153,7 +153,7 @@ void ruri_show_helps(void)
 	cprintf("{base}(*10) : This option need net ns, and will enable unshare feature by default\n");
 	cprintf("{base}(*11) : For example, `-I kvm 10 232` or `-I dri/card0 226 0`\n");
 	cprintf("{base}(*12) : This feature might not work. The value is in seconds. This feature will auto enable unshare\n");
-	cprintf("{base}{clear}\n");
+	cprintf("\n{base}Note:\n") cprintf("{base}BSD style usage is partially supported now, for example, you can use `-pW /root`, but `-W/root` is not allowed.\n") cprintf("{base}{clear}\n");
 }
 // For `ruri -H`.
 void ruri_show_examples(void)