what is this doing, please analyse following code snippet ...

Prompt

what is this doing, please analyse following code snippet case "$RAUC_IMAGE_NAME" in /*) IMG="$RAUC_IMAGE_NAME" ;; *) IMG="$(dirname "$(readlink -f "$0")")/$RAUC_IMAGE_NAME" ;; esac if [ ! -f "$IMG" ]; then log "slot-install: image $IMG not found in bundle" exit 1 fi