diff --git a/us.c b/us.c
index 69db7a7..f1647a4 100644
--- a/us.c
+++ b/us.c
@@ -42,6 +42,8 @@ static struct group* group_to_grp (const char *);
 // our own pam module
 static struct pam_conv conv = {misc_conv, NULL};
 
+extern char **environ;
+
 int main (int argc, char *argv[])
 {
 	// TODO: Add arguments
@@ -50,8 +52,8 @@ int main (int argc, char *argv[])
 	struct passwd *t_pw;
 	struct group *t_gr;
 	int opt, err;
-	int shellflag = 0;
-	while ((opt = getopt(argc, argv, "A:u:g:C:s")) != -1) {
+	int shellflag = 0, envflag = 0;
+	while ((opt = getopt(argc, argv, "A:u:g:C:se")) != -1) {
 		switch (opt) {
 		case 'A':
 			printf("-A is not yet implemented\n");
@@ -70,6 +72,9 @@ int main (int argc, char *argv[])
 		case 's':
 			shellflag = 1;
 			break;
+		case 'e':
+			envflag = 1;
+			break;
 		case '?':
 			usage();
 			exit(EINVAL);
@@ -139,33 +144,49 @@ int main (int argc, char *argv[])
 	if (authenticate(uname) != PAM_SUCCESS)
 		exit(EXIT_FAILURE);
 
-	// TODO: clean up env
-	/* copy and filter env */
-/*
-	char **c_env;
-	extern char **environ;
-	int size = 0;
-	for (int i = 0; environ[i]; i++, size++);
-	c_env = malloc(sizeof(char *) * (size + 1));
-	if (!c_env) {
-		fprintf(stderr, "malloc: %s\n", strerror(errno));
-		exit(errno);
+	struct env_elem {
+		char *name;
+		char *value;
+	};
+
+	struct env_elem env_keep[] = {
+		{"PATH", NULL},
+		{"TERM", NULL},
+		{"EDITOR", NULL},
+		{"VISUAL", NULL},
+		{"DISPLAY", NULL},
+		{"XAUTHORITY", NULL},
+		{NULL, NULL}
+	};
+
+	struct env_elem env_mod[] = {
+		{"USER", t_pw->pw_name},
+		{"LOGNAME", t_pw->pw_name},
+		{"SHELL", t_pw->pw_shell},
+		{"HOME", t_pw->pw_dir},
+		{NULL, NULL}
+	};
+
+	if (envflag) {	/* clear env */
+		for (int i = 0; env_keep[i].name; i++)
+			env_keep[i].value = strdup(getenv(env_keep[i].name));
+		environ = NULL; // in place of clearenv
 	}
-	for (int i = 0; environ[i]; i++) {
-		c_env[i] = strdup(environ[i]);
-		if (!c_env[i]) {
-			fprintf(stderr, "strdup: %s\n", strerror(errno));
-			exit(errno);
+
+	for (int i = 0; env_mod[i].name; i++) {
+		// TODO: check err value
+		err = setenv(env_mod[i].name, env_mod[i].value, 1);
+	}
+
+	if (envflag) {
+		for (int i = 0; env_keep[i].name; i++) {
+			// TODO: check err value
+			if (env_keep[i].value)
+				err = setenv(env_keep[i].name, env_keep[i].value, 1);
 		}
 	}
-	c_env[size] = NULL;
-*/
-	// TODO: check err value
-	// TODO: add all this to list and loop over it
-	err = setenv("USER", t_pw->pw_name, 1);
-	err = setenv("LOGNAME", t_pw->pw_name, 1);
-	err = setenv("SHELL", t_pw->pw_shell, 1);
-	err = setenv("HOME", t_pw->pw_dir, 1);
+	// do not override, we might be under more levels of 'us'
+	err = setenv("US_USER", my_pw->pw_name, 0);
 
 	errno = 0;
 	/* Set permissions */
@@ -198,7 +219,7 @@ static inline void usage (void)
 	// -c [file]: manually select config file
 	// something about environment
 	// something about non interactiveness
-	printf("usage: us [-s] [-u user] [-g group] command [args]\n");
+	printf("usage: us [-se] [-u user] [-g group] command [args]\n");
 }
 
 static int perm_set (struct passwd *pw, struct group *gr)