Normalize shebangs to #!/usr/bin/env bash (x-env-list, x-localip).
Use XDG_CONFIG_HOME in x-change-alacritty-theme. Remove unused
VERBOSE variable in x-multi-ping. Add set -euo pipefail to x-when-down
and x-when-up. Add usage header to x-term-colors. Fix notify-call
to notify-send.sh in x-record.
