diff --git a/src/exec.cpp b/src/exec.cpp
index bd24f5281..1557caf0b 100644
--- a/src/exec.cpp
+++ b/src/exec.cpp
@@ -428,9 +428,16 @@ static bool exec_internal_builtin_proc(parser_t &parser, const std::shared_ptr<j
         }
     }
 
+    // Pull out the IOs for stdout and stderr.
+    auto out_io = proc_io_chain.io_for_fd(STDOUT_FILENO);
+    auto err_io = proc_io_chain.io_for_fd(STDERR_FILENO);
+
+    // Set up our streams.
     streams.stdin_fd = local_builtin_stdin;
-    streams.out_is_redirected = proc_io_chain.io_for_fd(STDOUT_FILENO) != nullptr;
-    streams.err_is_redirected = proc_io_chain.io_for_fd(STDERR_FILENO) != nullptr;
+    streams.out_is_redirected = out_io != nullptr;
+    streams.err_is_redirected = err_io != nullptr;
+    streams.out_is_piped = (out_io != nullptr && out_io->io_mode == io_mode_t::pipe);
+    streams.err_is_piped = (err_io != nullptr && err_io->io_mode == io_mode_t::pipe);
     streams.stdin_is_directly_redirected = stdin_is_directly_redirected;
     streams.io_chain = &proc_io_chain;
 
diff --git a/src/io.h b/src/io.h
index ccaa67eb2..39d286e74 100644
--- a/src/io.h
+++ b/src/io.h
@@ -451,7 +451,12 @@ struct io_streams_t {
     // < foo.txt
     bool stdin_is_directly_redirected{false};
 
-    // Indicates whether stdout and stderr are redirected (e.g. to a file or piped).
+    // Indicates whether stdout and stderr are specifically piped.
+    // If this is set, then the is_redirected flags must also be set.
+    bool out_is_piped{false};
+    bool err_is_piped{false};
+
+    // Indicates whether stdout and stderr are at all redirected (e.g. to a file or piped).
     bool out_is_redirected{false};
     bool err_is_redirected{false};