diff --git a/io.cpp b/io.cpp
index 6a304014c..42c55f9fe 100644
--- a/io.cpp
+++ b/io.cpp
@@ -51,6 +51,28 @@ Utilities for io redirection.
 #include "io.h"
 
 
+void io_data_t::print() const
+{
+    switch (io_mode)
+    {
+        case IO_FILE:
+            fprintf(stderr, "file (%s)\n", filename_cstr);
+            break;
+        case IO_PIPE:
+            fprintf(stderr, "pipe {%d, %d}\n", param1.pipe_fd[0], param1.pipe_fd[1]);
+            break;
+        case IO_FD:
+            fprintf(stderr, "FD map %d -> %d\n", param1.old_fd, fd);
+            break;
+        case IO_BUFFER:
+            fprintf(stderr, "buffer %p (size %lu)\n", out_buffer_ptr(), out_buffer_size());
+            break;
+        case IO_CLOSE:
+            fprintf(stderr, "close %d\n", fd);
+            break;
+    }
+}
+
 void io_buffer_read(io_data_t *d)
 {
     exec_close(d->param1.pipe_fd[1]);
@@ -195,24 +217,7 @@ void io_print(const io_chain_t &chain)
     {
         const shared_ptr<const io_data_t> &io = chain.at(i);
         fprintf(stderr, "\t%lu: fd:%d, input:%s, ", (unsigned long)i, io->fd, io->is_input ? "yes" : "no");
-        switch (io->io_mode)
-        {
-            case IO_FILE:
-                fprintf(stderr, "file (%s)\n", io->filename_cstr);
-                break;
-            case IO_PIPE:
-                fprintf(stderr, "pipe {%d, %d}\n", io->param1.pipe_fd[0], io->param1.pipe_fd[1]);
-                break;
-            case IO_FD:
-                fprintf(stderr, "FD map %d -> %d\n", io->param1.old_fd, io->fd);
-                break;
-            case IO_BUFFER:
-                fprintf(stderr, "buffer %p (size %lu)\n", io->out_buffer_ptr(), io->out_buffer_size());
-                break;
-            case IO_CLOSE:
-                fprintf(stderr, "close %d\n", io->fd);
-                break;
-        }
+        io->print();
     }
 }
 
diff --git a/io.h b/io.h
index 96f5cbaf4..da47abe07 100644
--- a/io.h
+++ b/io.h
@@ -94,6 +94,8 @@ public:
         return out_buffer->size();
     }
 
+    virtual void print() const;
+
     /** Set to true if this is an input io redirection */
     bool is_input;