diff --git a/README b/README
index f81001f..d62ed04 100644
--- a/README
+++ b/README
@@ -12,4 +12,5 @@
 
 TODO:
 - [o] "#load" pragma
+- [o  better dip/keep (avoid using the retain stack for them)
 - [ ] hand-rolled parser
diff --git a/examples/cat.grr b/examples/cat.grr
new file mode 100644
index 0000000..f475451
--- /dev/null
+++ b/examples/cat.grr
@@ -0,0 +1,11 @@
+#load("std.grr")
+
+def while {
+  swap dup bury >r >r
+  if: call dup
+    [r> dup >r call r> r> swap while]
+    [drop r> drop r> drop];
+}
+
+while: [stdin fgetline]
+  [print];
diff --git a/src/file.c b/src/file.c
index 8807182..1aa010c 100644
--- a/src/file.c
+++ b/src/file.c
@@ -1,5 +1,8 @@
 #include <stdio.h>
+#include <stdlib.h>
 
+#include "src/gc.h"
+#include "src/object.h"
 #include "string.h"
 #include "userdata.h"
 #include "vm.h"
@@ -13,6 +16,11 @@ Ut userdata_file = {
 };
 // clang-format on
 
+I prim_file_stdin(Vm *vm) {
+  vm_push(vm, vm->stdin);
+  return 0;
+}
+
 I prim_file_stdout(Vm *vm) {
   vm_push(vm, vm->stdout);
   return 0;
@@ -29,13 +37,13 @@ I prim_file_fprint(Vm *vm) {
 
   Ud *file_ud = userdata_unwrap(file_obj, &userdata_file);
   if (file_ud == NULL) {
-    fprintf(stderr, "expected file object");
+    fprintf(stderr, "expected file object\n");
     return VM_ERR_TYPE;
   };
 
   Str *str = string_unwrap(string_obj);
   if (str == NULL) {
-    fprintf(stderr, "expected string");
+    fprintf(stderr, "expected string\n");
     return VM_ERR_TYPE;
   }
 
@@ -43,6 +51,31 @@ I prim_file_fprint(Vm *vm) {
   return 0;
 }
 
+I prim_file_fgetline(Vm *vm) {
+  O file_obj = vm_pop(vm);
+  I mark = gc_mark(&vm->gc);
+  gc_addroot(&vm->gc, &file_obj);
+
+  Ud *file_ud = userdata_unwrap(file_obj, &userdata_file);
+  if (file_ud == NULL) {
+    fprintf(stderr, "expected file object\n");
+    return VM_ERR_TYPE;
+  }
+
+  char *lineptr = NULL;
+  size_t size;
+  I len = getline(&lineptr, &size, (FILE *)file_ud->data);
+  if (len == -1) {
+    vm_push(vm, NIL);
+  } else {
+    vm_push(vm, string_make(vm, lineptr, len));
+  }
+  free(lineptr);
+
+  gc_reset(&vm->gc, mark);
+  return 0;
+}
+
 static V finalizer(V *data) {
   FILE *f = (FILE *)data;
   if (f && f != stdin && f != stdout && f != stderr)
diff --git a/src/file.h b/src/file.h
index fa73f79..cb10b11 100644
--- a/src/file.h
+++ b/src/file.h
@@ -2,6 +2,8 @@
 
 extern Ut userdata_file;
 
+I prim_file_stdin(Vm *);
 I prim_file_stdout(Vm *);
 I prim_file_stderr(Vm *);
 I prim_file_fprint(Vm *);
+I prim_file_fgetline(Vm *vm);
diff --git a/src/primitive.c b/src/primitive.c
index 7f68c1f..983112e 100644
--- a/src/primitive.c
+++ b/src/primitive.c
@@ -28,9 +28,11 @@ static I prim_printstack(Vm *vm) {
 Pr primitives_table[] = {
   {".", prim_pprint},
   {".s", prim_printstack},
+  {"stdin", prim_file_stdin},
   {"stdout", prim_file_stdout},
   {"stderr", prim_file_stderr},
   {"fprint", prim_file_fprint},
+  {"fgetline", prim_file_fgetline},
   {NULL, NULL},
 };
 // clang-format on
diff --git a/src/print.c b/src/print.c
index 53bdcb8..1407963 100644
--- a/src/print.c
+++ b/src/print.c
@@ -21,6 +21,7 @@ V print(O o) {
       printf("<quotation>");
       break;
     case OBJ_STR: {
+      // TODO: make this binary safe
       Str *s = string_unwrap(o);
       char *escaped = malloc(s->len + 1);
       memcpy(escaped, s->data, s->len);