diff --git a/dockershell.sh b/dockershell.sh
index 4996fcc..e206b18 100755
--- a/dockershell.sh
+++ b/dockershell.sh
@@ -1,3 +1,6 @@
 #!/bin/bash
 
-docker run -it fredericklab/capcalc xyzzy
+VERSION=latest
+
+docker pull fredericklab/capcalc:${VERSION}
+docker run -it fredericklab/capcalc:${VERSION} xyzzy
diff --git a/testdocker.sh b/testdocker.sh
index 18deadc..2ed71d3 100755
--- a/testdocker.sh
+++ b/testdocker.sh
@@ -1,14 +1,16 @@
 #!/bin/bash
 
 MYIPADDRESS=`ifconfig en0 | grep 'inet ' | awk '{print $2}'`
+VERSION=latest
 
+docker pull fredericklab/capcalc:${VERSION}
 docker run \
     --rm \
     --ipc host \
     --mount type=bind,source=/Users/frederic/code/capcalc/capcalc/data/,destination=/data \
     -it \
     -v /tmp/.X11-unix:/tmp/.X11-unix \
-    -u capcalc fredericklab/capcalc:latest \
+    -u capcalc fredericklab/capcalc:${VERSION} \
     capfromtcs \
         -i /data/manyfiles.txt \
         -o /data/output/manyfiles \