set -eE -o pipefail
trap 'echo "$0:$LINENO:error: \"$BASH_COMMAND\" returned $?"' ERR
-readonly this_file; this_file="$(readlink -f -- "${BASH_SOURCE[0]}")"; cd ${this_file%/*}
+this_file="$(readlink -f -- "${BASH_SOURCE[0]}")"
+readonly this_file this_dir="${this_file%/*}"
+cd "$this_dir"
# get rid of useless motd stuff
sed -i --follow-symlinks 's/^\s*PrintLastLog .*/PrintLastLog no/' /etc/ssh/sshd_config
rm -f /etc/update-motd.d/10-help-text /etc/update-motd.d/00-header