Whether to run shellcheck on the generated scripts for systemd units.
When enabled, all systemd scripts generated by NixOS will be checked with shellcheck and any errors or warnings will cause the build to fail.
This affects all scripts that have been created through the script, reload, preStart, postStart, preStop and postStop options for systemd services. This does not affect command lines passed directly to ExecStart, ExecReload, ExecStartPre, ExecStartPost, ExecStop or ExecStopPost.
It therefore also does not affect systemd units that are coming from packages and that are not defined through the NixOS config. This option is disabled by default, and although some services have already been fixed, it is still likely that you will encounter build failures when enabling this.
We encourage people to enable this option when they are willing and able to submit fixes for potential build failures to Nixpkgs. The option can also be enabled or disabled for individual services using the enableStrictShellChecks option on the service itself, which will take precedence over the global setting.