🦄 refactor(C14, C15):

C14-文件系统/fs/username.c

@@ -0,0 +1,29 @@
+#include <pwd.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+/**
+ * @brief    用user id获取用户名
+ * @details
+ *
+ * @param    argc
+ * @param    argv
+ *
+ * @return  int
+ */
+int main(int argc, char **argv)
+{
+    if (argc < 2)
+    {
+        fprintf(stderr, "Usage: %s <user id>\n", argv[0]);
+        exit(1);
+    }
+
+    struct passwd *pwdline;
+
+    pwdline = getpwuid(atoi(argv[1]));
+
+    puts(pwdline->pw_name);
+
+    exit(0);
+}