diff --git a/docker/runner/slack.json b/docker/runner/slack.json
index d00bd5002ab568d6cbb4ccbc21a53efee176f857..ecde173467c65e220fb63db9cf405a0640e721c2 100644
--- a/docker/runner/slack.json
+++ b/docker/runner/slack.json
@@ -1 +1 @@
-{"channel": "#dev-activity", "username": "webhookbot", "text": "${USER^} pushed a new version of hbpmip/portal-backend to Docker hub", "icon_emoji": ":whale:"}
+{"channel": "#dev-activity", "username": "webhookbot", "text": "USER pushed a new version of hbpmip/portal-backend to Docker hub", "icon_emoji": ":whale:"}
diff --git a/docker_push.sh b/docker_push.sh
index fdf341b3bc7d810d0abf2b7725746ddc32cb1e6a..e064f55369d171f1b5f5a3716d48d4bd5305afc2 100755
--- a/docker_push.sh
+++ b/docker_push.sh
@@ -27,6 +27,6 @@ else
 fi
 
 $CAPTAIN push --branch-tags=false --commit-tags=true portal-backend
-eval "echo $(cat $WORKSPACE/docker/runner/slack.json)" > $WORKSPACE/target/slack.json
+cat $WORKSPACE/docker/runner/slack.json | sed "s/USER/${USER^}/" > $WORKSPACE/target/slack.json
 curl -k -X POST --data-urlencode payload@$WORKSPACE/target/slack.json https://hbps1.chuv.ch/slack/dev-activity
 rm -f $WORKSPACE/target/slack.json