diff --git a/.gitignore b/.gitignore
index 9d986ba..d3ebcdf 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,6 +9,7 @@ gitignore*
 # Specific files.
 /9p
 /README.html
+/trace-[0-9]*
 
 # GEM5
 /m5out
diff --git a/README.adoc b/README.adoc
index 71c41ee..17a1862 100644
--- a/README.adoc
+++ b/README.adoc
@@ -3240,6 +3240,22 @@ Does not work for subdirectories, gem5 crashes:
 m5 writefile myfileguest mydirhost/myfilehost
 ....
 
+==== m5 readfile
+
+https://stackoverflow.com/questions/49516399/how-to-use-m5-readfile-and-m5-execfile-in-gem5/49538051#49538051
+
+Host:
+
+....
+date >m5out/myreadfile
+....
+
+Guest:
+
+....
+m5 readfile
+....
+
 === gem5 limitations
 
 * networking not working. We currently just disable it from `inittab` by default to prevent waiting at startup
diff --git a/run b/run
index 8cbe7c0..412788d 100755
--- a/run
+++ b/run
@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-set -e
+set -eu
 . common
 
 # CLI handling.
@@ -121,7 +121,8 @@ if "$gem5"; then
   else
     gem5_arch=ARM
   fi
-  gem5_cpt_dir="./m5out/cpts/${arch}"
+  m5out_dir="${root_dir}/m5out"
+  gem5_cpt_dir="${m5out_dir}/cpts/${arch}"
   mkdir -p "$gem5_cpt_dir"
   gem5_common="\
 M5_PATH='${build_dir}/system' \
@@ -134,6 +135,7 @@ ${gem5opts} \
 --kernel='${out_dir}/build/linux-custom/vmlinux' \
 --mem-size=${memory} \
 --num-cpus='${cpus}' \
+--script='${m5out_dir}/myreadfile' \
 "
   if [ "$arch" = x86_64 ]; then
     if "$kvm"; then