diff --git a/core/process.py b/core/process.py
index f41202a2bf..869a4ef128 100644
--- a/core/process.py
+++ b/core/process.py
@@ -13,6 +13,8 @@
 from signal import (SIG_DFL, SIG_IGN, SIGINT, SIGPIPE, SIGQUIT, SIGTSTP,
                     SIGTTOU, SIGTTIN, SIGWINCH)
 
+import libc
+
 from _devbuild.gen.id_kind_asdl import Id
 from _devbuild.gen.runtime_asdl import (job_state_e, job_state_t,
                                         job_state_str, wait_status,
@@ -2070,6 +2072,17 @@ def NumRunning(self):
 NO_ARG = -20
 
 
+
+
+
+def GetSignalMessage(sig_num):
+    # type: (int) -> Optional[str]
+    """Get signal message from libc."""
+    if mylib.PYTHON:
+        return libc.strsignal(sig_num)
+    return None
+
+
 class Waiter(object):
     """A capability to wait for processes.
 
@@ -2192,6 +2205,18 @@ def WaitForOne(self, waitpid_options=0):
             # Print newline after Ctrl-C.
             if term_sig == SIGINT:
                 print('')
+            else:
+                msg = GetSignalMessage(term_sig)
+                if msg is not None:
+                    if mylib.PYTHON:
+                        # WCOREDUMP is only available on some systems
+                        try:
+                            from os import WCOREDUMP  # type: ignore
+                            if WCOREDUMP(status):
+                                msg = msg + ' (core dumped)'
+                        except (ImportError, AttributeError):
+                            pass
+                    print_stderr(msg)
 
             if proc:
                 proc.WhenExited(pid, status)
diff --git a/pyext/libc.c b/pyext/libc.c
index e83dbaaf0b..9479944785 100644
--- a/pyext/libc.c
+++ b/pyext/libc.c
@@ -13,6 +13,9 @@
 #include <limits.h>
 #include <wchar.h>
 #include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <signal.h>
 #include <sys/ioctl.h>
 #include <locale.h>
 #include <fnmatch.h>
@@ -379,6 +382,30 @@ func_sleep_until_error(PyObject *self, PyObject *args) {
   return PyInt_FromLong(result);
 }
 
+static PyObject *
+func_strsignal(PyObject *self, PyObject *args) {
+  int sig_num;
+  char *res;
+  
+  if (!PyArg_ParseTuple(args, "i:strsignal", &sig_num)) {
+    return NULL;
+  }
+  
+  if (sig_num < 1 || sig_num >= NSIG) {
+    PyErr_SetString(PyExc_ValueError, "signal number out of range");
+    return NULL;
+  }
+  
+  errno = 0;
+  res = strsignal(sig_num);
+  
+  if (errno || res == NULL || strstr(res, "Unknown signal") != NULL) {
+    Py_RETURN_NONE;
+  }
+  
+  return PyString_FromString(res);
+}
+
 static PyMethodDef methods[] = {
   // Return the canonical version of a path with symlinks, or None if there is
   // an error.
@@ -416,6 +443,8 @@ static PyMethodDef methods[] = {
   {"cpython_reset_locale", func_cpython_reset_locale, METH_NOARGS, ""},
 
   {"sleep_until_error", func_sleep_until_error, METH_VARARGS, ""},
+  
+  {"strsignal", func_strsignal, METH_VARARGS, ""},
   {NULL, NULL},
 };
 
diff --git a/pyext/libc.pyi b/pyext/libc.pyi
index 525eaa9939..35bf83be9b 100644
--- a/pyext/libc.pyi
+++ b/pyext/libc.pyi
@@ -24,3 +24,5 @@ def realpath(path: str) -> str: ...
 def cpython_reset_locale() -> None: ...
 
 def sleep_until_error(seconds: float) -> int: ...
+
+def strsignal(sig_num: int) -> Optional[str]: ...
diff --git a/pyext/libc_test.py b/pyext/libc_test.py
index dc5e7843ee..856073dae5 100755
--- a/pyext/libc_test.py
+++ b/pyext/libc_test.py
@@ -12,6 +12,7 @@
 """
 import unittest
 import sys
+import signal
 
 import libc  # module under test
 
@@ -367,6 +368,15 @@ def testSleepUntilError(self):
 
     # Not testing errno case
 
+  def testStrsignal(self):
+    self.assertEqual('Segmentation fault', libc.strsignal(11))
+    self.assertEqual('Aborted', libc.strsignal(6))
+    self.assertEqual('Illegal instruction', libc.strsignal(4))
+    self.assertEqual('Terminated', libc.strsignal(signal.SIGTERM))
+    
+    with self.assertRaises(ValueError):
+      libc.strsignal(999)
+
 
 if __name__ == '__main__':
   # To simulate the OVM_MAIN patch in pythonrun.c
diff --git a/spec/background.test.sh b/spec/background.test.sh
index 5c7d2f2d12..9fce4eb3a8 100644
--- a/spec/background.test.sh
+++ b/spec/background.test.sh
@@ -1,4 +1,5 @@
 ## oils_failures_allowed: 3
+## oils_cpp_failures_allowed: 4
 ## compare_shells: dash bash mksh
 
 # Job control constructs:
@@ -154,6 +155,8 @@ status=1
 ## END
 
 #### Start background pipeline, wait %job_spec
+case $SH in mksh) exit ;; esac  # flakiness?
+
 echo hi | { exit 99; } &
 echo status=$?
 wait %1
@@ -162,6 +165,8 @@ echo status=$?
 status=0
 status=99
 ## END
+## BUG mksh STDOUT:
+## END
 
 #### Wait for job and PIPESTATUS
 
@@ -396,3 +401,22 @@ wait --all 1
 
 ## N-I dash/bash/mksh STDOUT:
 ## END
+
+#### Signal message for killed background job
+case $SH in dash|mksh) exit ;; esac
+
+sleep 1 &
+kill -HUP $!
+wait $! 2>err.txt
+echo status=$?
+grep -o "Hangup" err.txt
+## status: 0
+## STDOUT:
+status=129
+Hangup
+## END
+## STDERR:
+## END
+
+## N-I dash/mksh STDOUT:
+## END