The Squid part of DansGuardian/Squid has an option (squid -k parse) to parse or check the configuration without actually doing anything. But there's nothing similar built in to the DansGuardian part. When you attempt to start DansGuardian, some configuration errors will cause it to emit an error message and not start. But many other configuration errors –including misspelled options– are never detected.
Some problems can cause DansGuardian to behave differently than you intend, yet have been very difficult to locate. Such problems include not only subtle misspellings but also listing an option in the wrong config file (dansguardian.conf vs. dansguardianfN.conf) and listing an option twice. This tool will locate these and similar problems easily and accurately.
Use this standalone tool to scan your DansGuardian configuration and parse or check it. Run this tool occasionally, for example whenever modifying the DansGuardian base configuration (i.e. not just the '…list' files).
The tool runs on any Linux system where Perl is available. It is a single self-contained script file. Fetch the file, gunzip it, set execute permissions, and execute it from any shell prompt. The tool is initially named dgscan. Download the gzipped package here.