diff --git a/src/core/os.c b/src/core/os.c
index 70f0449ca..65afdce9d 100644
--- a/src/core/os.c
+++ b/src/core/os.c
@@ -1145,14 +1145,16 @@ static Janet os_execute_impl(int32_t argc, Janet *argv, int is_spawn) {
         posix_spawn_file_actions_addclose(&actions, pipe_in);
     } else if (new_in != JANET_HANDLE_NONE && new_in != 0) {
         posix_spawn_file_actions_adddup2(&actions, new_in, 0);
-        posix_spawn_file_actions_addclose(&actions, new_in);
+        if (new_in != new_out && new_in != new_err)
+            posix_spawn_file_actions_addclose(&actions, new_in);
     }
     if (pipe_out != JANET_HANDLE_NONE) {
         posix_spawn_file_actions_adddup2(&actions, pipe_out, 1);
         posix_spawn_file_actions_addclose(&actions, pipe_out);
     } else if (new_out != JANET_HANDLE_NONE && new_out != 1) {
         posix_spawn_file_actions_adddup2(&actions, new_out, 1);
-        posix_spawn_file_actions_addclose(&actions, new_out);
+        if (new_out != new_err)
+            posix_spawn_file_actions_addclose(&actions, new_out);
     }
     if (pipe_err != JANET_HANDLE_NONE) {
         posix_spawn_file_actions_adddup2(&actions, pipe_err, 2);
diff --git a/test/suite-os.janet b/test/suite-os.janet
index f88c997d3..881f24cfa 100644
--- a/test/suite-os.janet
+++ b/test/suite-os.janet
@@ -94,9 +94,9 @@
   (assert (= (length buf) 2) "cryptorand appends to buffer"))
 
 # 80db68210
-(assert-no-error (os/clock :realtime) "realtime clock")
-(assert-no-error (os/clock :cputime) "cputime clock")
-(assert-no-error (os/clock :monotonic) "monotonic clock")
+(assert-no-error "realtime clock" (os/clock :realtime))
+(assert-no-error "cputime clock" (os/clock :cputime))
+(assert-no-error "monotonic clock" (os/clock :monotonic))
 
 (def before (os/clock :monotonic))
 (def after (os/clock :monotonic))
@@ -129,5 +129,20 @@
                             (string/format "(os/exit %d)" i)] :p))
           (string "os/execute " i)))
 
+# os/execute IO redirection
+(assert-no-error "IO redirection"
+                 (defn devnull []
+                   (def os (os/which))
+                   (def path (if (or (= os :mingw) (= os :windows))
+                               "NUL"
+                               "/dev/null"))
+                   (os/open path :w))
+                 (with [dn (devnull)]
+                   (os/execute [(dyn :executable)
+                                "-e"
+                                "(print :foo) (eprint :bar)"]
+                               :px
+                               {:out dn :err dn})))
+
 (end-suite)