--- gnuser-1.2.0.c	2009-11-05 21:53:41.000000000 +0100
+++ gnuser-1.2.1.c	2009-11-05 21:54:43.000000000 +0100
@@ -1,7 +1,7 @@
 /*
  * Project: gnuser (Gnu User Manager)
  * File: gnuser.c
- * Version: 1.2.0
+ * Version: 1.2.1
  * Copyright (c) 2009-2010
  * Author: Jonathan Salwan
  * Mail: jonathan.salwan [!] gnuser.org  
@@ -119,7 +119,7 @@
 static void version(void)
 {
         fprintf(stdout,
-			"gnuser (Gnu User Manager) - v1.2.0\n"
+			"gnuser (Gnu User Manager) - v1.2.1\n"
 			"GPL Licence\n");
 
 exit(0);
@@ -205,6 +205,26 @@
 return 0;
 }
 
+int verif_uid(int idlogin)
+{
+
+	FILE *fileread;
+
+	fileread  = fopen(patch_passwd, "r");
+	struct passwd *pswd_struct; /* Structur passwd file entry  */
+
+	while ((pswd_struct = fgetpwent(fileread)) != NULL)
+		{			
+		if (pswd_struct->pw_uid == idlogin){ break; }
+     		}
+
+		/* test if uid exist */
+ 		if (pswd_struct == NULL)
+			{return 0;}
+			else
+			{return 1;}
+}
+
 int main(int argc, char *argv[])
 {
 
@@ -229,6 +249,12 @@
 		if(argc < 5)
 			option_add();
 
+			/* Verification if uid exist in /etc/passwd */
+			if(verif_uid(atoi(argv[3])) == 1){
+				fprintf(stderr,"Error: Uid exist, please change uid.\n");
+				exit(1);
+				}
+				
 			FILE *fichier;
 
 			/* write in /etc/passwd */