diff --git a/alpine.Dockerfile b/alpine.Dockerfile
index 4d94e79..993b022 100644
--- a/alpine.Dockerfile
+++ b/alpine.Dockerfile
@@ -36,12 +36,12 @@ ENV POSTGRES_DB="**None**" \
     WEBHOOK_EXTRA_ARGS=""
 
 COPY hooks /hooks
-COPY backup.sh /backup.sh
+COPY backup.sh env.sh init.sh /
 
 VOLUME /backups
 
 ENTRYPOINT ["/bin/sh", "-c"]
-CMD ["exec /usr/local/bin/go-cron -s \"$SCHEDULE\" -p \"$HEALTHCHECK_PORT\" -- /backup.sh"]
+CMD ["exec /init.sh"]
 
 HEALTHCHECK --interval=5m --timeout=3s \
   CMD curl -f "http://localhost:$HEALTHCHECK_PORT/" || exit 1
diff --git a/backup.sh b/backup.sh
index 4a5066a..cbb82dc 100755
--- a/backup.sh
+++ b/backup.sh
@@ -9,64 +9,7 @@ if [ -d "${HOOKS_DIR}" ]; then
   trap 'on_error' ERR
 fi
 
-if [ "${POSTGRES_DB}" = "**None**" -a "${POSTGRES_DB_FILE}" = "**None**" ]; then
-  echo "You need to set the POSTGRES_DB or POSTGRES_DB_FILE environment variable."
-  exit 1
-fi
-
-if [ "${POSTGRES_HOST}" = "**None**" ]; then
-  if [ -n "${POSTGRES_PORT_5432_TCP_ADDR}" ]; then
-    POSTGRES_HOST=${POSTGRES_PORT_5432_TCP_ADDR}
-    POSTGRES_PORT=${POSTGRES_PORT_5432_TCP_PORT}
-  else
-    echo "You need to set the POSTGRES_HOST environment variable."
-    exit 1
-  fi
-fi
-
-if [ "${POSTGRES_USER}" = "**None**" -a "${POSTGRES_USER_FILE}" = "**None**" ]; then
-  echo "You need to set the POSTGRES_USER or POSTGRES_USER_FILE environment variable."
-  exit 1
-fi
-
-if [ "${POSTGRES_PASSWORD}" = "**None**" -a "${POSTGRES_PASSWORD_FILE}" = "**None**" -a "${POSTGRES_PASSFILE_STORE}" = "**None**" ]; then
-  echo "You need to set the POSTGRES_PASSWORD or POSTGRES_PASSWORD_FILE or POSTGRES_PASSFILE_STORE environment variable or link to a container named POSTGRES."
-  exit 1
-fi
-
-#Process vars
-if [ "${POSTGRES_DB_FILE}" = "**None**" ]; then
-  POSTGRES_DBS=$(echo "${POSTGRES_DB}" | tr , " ")
-elif [ -r "${POSTGRES_DB_FILE}" ]; then
-  POSTGRES_DBS=$(cat "${POSTGRES_DB_FILE}")
-else
-  echo "Missing POSTGRES_DB_FILE file."
-  exit 1
-fi
-if [ "${POSTGRES_USER_FILE}" = "**None**" ]; then
-  export PGUSER="${POSTGRES_USER}"
-elif [ -r "${POSTGRES_USER_FILE}" ]; then
-  export PGUSER=$(cat "${POSTGRES_USER_FILE}")
-else
-  echo "Missing POSTGRES_USER_FILE file."
-  exit 1
-fi
-if [ "${POSTGRES_PASSWORD_FILE}" = "**None**" -a "${POSTGRES_PASSFILE_STORE}" = "**None**" ]; then
-  export PGPASSWORD="${POSTGRES_PASSWORD}"
-elif [ -r "${POSTGRES_PASSWORD_FILE}" ]; then
-  export PGPASSWORD=$(cat "${POSTGRES_PASSWORD_FILE}")
-elif [ -r "${POSTGRES_PASSFILE_STORE}" ]; then
-  export PGPASSFILE="${POSTGRES_PASSFILE_STORE}"
-else
-  echo "Missing POSTGRES_PASSWORD_FILE or POSTGRES_PASSFILE_STORE file."
-  exit 1
-fi
-export PGHOST="${POSTGRES_HOST}"
-export PGPORT="${POSTGRES_PORT}"
-KEEP_MINS=${BACKUP_KEEP_MINS}
-KEEP_DAYS=${BACKUP_KEEP_DAYS}
-KEEP_WEEKS=`expr $(((${BACKUP_KEEP_WEEKS} * 7) + 1))`
-KEEP_MONTHS=`expr $(((${BACKUP_KEEP_MONTHS} * 31) + 1))`
+source "$(dirname "$0")/env.sh"
 
 # Pre-backup hook
 if [ -d "${HOOKS_DIR}" ]; then
diff --git a/debian.Dockerfile b/debian.Dockerfile
index 5b77f8c..2af98ed 100644
--- a/debian.Dockerfile
+++ b/debian.Dockerfile
@@ -50,12 +50,12 @@ ENV POSTGRES_DB="**None**" \
     WEBHOOK_EXTRA_ARGS=""
 
 COPY hooks /hooks
-COPY backup.sh /backup.sh
+COPY backup.sh env.sh init.sh /
 
 VOLUME /backups
 
 ENTRYPOINT ["/bin/sh", "-c"]
-CMD ["exec /usr/local/bin/go-cron -s \"$SCHEDULE\" -p \"$HEALTHCHECK_PORT\" -- /backup.sh"]
+CMD ["exec /init.sh"]
 
 HEALTHCHECK --interval=5m --timeout=3s \
   CMD curl -f "http://localhost:$HEALTHCHECK_PORT/" || exit 1
diff --git a/env.sh b/env.sh
new file mode 100755
index 0000000..ccbe801
--- /dev/null
+++ b/env.sh
@@ -0,0 +1,68 @@
+#!/usr/bin/env bash
+# Pre-validate the environment
+if [ "${POSTGRES_DB}" = "**None**" -a "${POSTGRES_DB_FILE}" = "**None**" ]; then
+  echo "You need to set the POSTGRES_DB or POSTGRES_DB_FILE environment variable."
+  exit 1
+fi
+
+if [ "${POSTGRES_HOST}" = "**None**" ]; then
+  if [ -n "${POSTGRES_PORT_5432_TCP_ADDR}" ]; then
+    POSTGRES_HOST=${POSTGRES_PORT_5432_TCP_ADDR}
+    POSTGRES_PORT=${POSTGRES_PORT_5432_TCP_PORT}
+  else
+    echo "You need to set the POSTGRES_HOST environment variable."
+    exit 1
+  fi
+fi
+
+if [ "${POSTGRES_USER}" = "**None**" -a "${POSTGRES_USER_FILE}" = "**None**" ]; then
+  echo "You need to set the POSTGRES_USER or POSTGRES_USER_FILE environment variable."
+  exit 1
+fi
+
+if [ "${POSTGRES_PASSWORD}" = "**None**" -a "${POSTGRES_PASSWORD_FILE}" = "**None**" -a "${POSTGRES_PASSFILE_STORE}" = "**None**" ]; then
+  echo "You need to set the POSTGRES_PASSWORD or POSTGRES_PASSWORD_FILE or POSTGRES_PASSFILE_STORE environment variable or link to a container named POSTGRES."
+  exit 1
+fi
+
+#Process vars
+if [ "${POSTGRES_DB_FILE}" = "**None**" ]; then
+  POSTGRES_DBS=$(echo "${POSTGRES_DB}" | tr , " ")
+elif [ -r "${POSTGRES_DB_FILE}" ]; then
+  POSTGRES_DBS=$(cat "${POSTGRES_DB_FILE}")
+else
+  echo "Missing POSTGRES_DB_FILE file."
+  exit 1
+fi
+if [ "${POSTGRES_USER_FILE}" = "**None**" ]; then
+  export PGUSER="${POSTGRES_USER}"
+elif [ -r "${POSTGRES_USER_FILE}" ]; then
+  export PGUSER=$(cat "${POSTGRES_USER_FILE}")
+else
+  echo "Missing POSTGRES_USER_FILE file."
+  exit 1
+fi
+if [ "${POSTGRES_PASSWORD_FILE}" = "**None**" -a "${POSTGRES_PASSFILE_STORE}" = "**None**" ]; then
+  export PGPASSWORD="${POSTGRES_PASSWORD}"
+elif [ -r "${POSTGRES_PASSWORD_FILE}" ]; then
+  export PGPASSWORD=$(cat "${POSTGRES_PASSWORD_FILE}")
+elif [ -r "${POSTGRES_PASSFILE_STORE}" ]; then
+  export PGPASSFILE="${POSTGRES_PASSFILE_STORE}"
+else
+  echo "Missing POSTGRES_PASSWORD_FILE or POSTGRES_PASSFILE_STORE file."
+  exit 1
+fi
+export PGHOST="${POSTGRES_HOST}"
+export PGPORT="${POSTGRES_PORT}"
+KEEP_MINS=${BACKUP_KEEP_MINS}
+KEEP_DAYS=${BACKUP_KEEP_DAYS}
+KEEP_WEEKS=`expr $(((${BACKUP_KEEP_WEEKS} * 7) + 1))`
+KEEP_MONTHS=`expr $(((${BACKUP_KEEP_MONTHS} * 31) + 1))`
+
+# Validate backup dir
+if [ -d "${BACKUP_DIR}" -a -w "${BACKUP_DIR}" -a -x "${BACKUP_DIR}" ]; then
+  echo "Backups will be stored at ${BACKUP_DIR}."
+else
+  echo "BACKUP_DIR points to a file or folder with insufficient permissions."
+  exit 1
+fi
diff --git a/init.sh b/init.sh
new file mode 100755
index 0000000..8674bff
--- /dev/null
+++ b/init.sh
@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+set -Eeo pipefail
+
+# Prevalidate configuration (don't source)
+/env.sh
+
+exec /usr/local/bin/go-cron -s "$SCHEDULE" -p "$HEALTHCHECK_PORT" -- /backup.sh