Perl Debugger vs UDE Universal Debug Engine

Perl Debugger is an interactive debugger included with Perl, not a separate program. Running Perl with the `-d` flag loads the debugger and adds source information, allowing users to inspect code, set breakpoints, view stack backtraces, and change variable values. The program must compile correctly before debugging.

Debugger commands support stepping into subroutine calls, stepping over them, and tracing execution. Conditional breakpoints and watches on global expressions can pause a run when specified conditions or changes occur. The `x` command can pretty-print nested data; displaying lexical variables requires PadWalker version 0.08 or higher. Options can be set interactively, through `PERLDB_OPTS`, or in `.perldb` files. Documentation also describes a GUI option through Devel::ptkdb. The debugger does not provide stack-frame information for functions not compiled by Perl, such as C or C++ extension functions, and compile-time executable statements are not stopped, though some can be traced with AutoTrace. Perl is listed for Linux, macOS, and Windows, and the debugger is free.

UDE Universal Debug Engine has no write-up on Specifiction yet; its figures are above.