diff --git a/eval.c b/eval.c
index 00845b28..4588a1a4 100644
--- a/eval.c
+++ b/eval.c
@@ -778,7 +778,15 @@ int main (int argc, char **argv) {
   for (i=1; i < argc && argv[i][0] == '-'; i++) {
     switch (argv[i][1]) {
     case 'e':
+    case 'p':
+      obj = sexp_read_from_string(argv[i+1]);
+      res = eval_in_stack(obj, e, stack, 0);
+      if (argv[i][1] == 'p') {
+        sexp_write(res, cur_output_port);
+        sexp_write_char('\n', cur_output_port);
+      }
       quit=1;
+      i++;
       break;
     default:
       errx(1, "unknown option: %s", argv[i]);
diff --git a/sexp.c b/sexp.c
index 16c060c5..eb180664 100644
--- a/sexp.c
+++ b/sexp.c
@@ -753,6 +753,15 @@ sexp sexp_read (sexp in) {
   return res;
 }
 
+sexp sexp_read_from_string(char *str) {
+  sexp s = sexp_make_string(str);
+  sexp in = sexp_make_input_string_port(s);
+  sexp res = sexp_read(in);
+  sexp_free(s);
+  sexp_free(in);
+  return res;
+}
+
 void sexp_init() {
   if (! sexp_initialized_p) {
     sexp_initialized_p = 1;
diff --git a/sexp.h b/sexp.h
index 729110fb..fed7ae22 100644
--- a/sexp.h
+++ b/sexp.h
@@ -232,6 +232,7 @@ char* sexp_read_symbol(sexp in, int init);
 sexp sexp_read_number(sexp in, int base);
 sexp sexp_read_raw(sexp in);
 sexp sexp_read(sexp in);
+sexp sexp_read_from_string(char *str);
 sexp sexp_make_input_port(FILE* in);
 sexp sexp_make_output_port(FILE* out);
 sexp sexp_make_input_string_port(sexp str);