Switch from egrep to grep -E

Author: thespad

Dockerfile

@@ -25,13 +25,13 @@ RUN \
   # Somehow figure out version detection and download URL here
   if [ -z ${APP_VERSION+x} ]; then \
     APP_VERSION=$(curl -sL https://www.tp-link.com/uk/support/download/omada-software-controller/ \
-    | egrep -m 1 -io 'https?://[^ ]+.tar.gz' \
+    | grep -E -m 1 -io 'https?://[^ ]+.tar.gz' \
     | awk -F "/" '{print $NF}' \
     | awk -F '_' '{print $4}'); \
   fi && \
   mkdir -p /tmp/omada && \
   OMADA_DOWNLOAD=$(curl -sL https://www.tp-link.com/uk/support/download/omada-software-controller/ \
-    | egrep -io "https?://[^ ]+${APP_VERSION}_linux_x64.tar.gz") && \
+    | grep -E -io "https?://[^ ]+${APP_VERSION}_linux_x64.tar.gz") && \
   # Download Omada package, try and handle their appalling packaging "standards"
   curl -o \
     /tmp/omada.tar.gz -L \