-=item B<-D>I<list>
-
-sets debugging flags. To watch how it executes your script, use
-B<-D14>. (This works only if debugging is compiled into your
-Perl.) Another nice value is B<-D1024>, which lists your compiled
-syntax tree. And B<-D512> displays compiled regular expressions. As an
-alternative specify a list of letters instead of numbers (e.g., B<-D14> is
-equivalent to B<-Dtls>):
-
- 1 p Tokenizing and Parsing
- 2 s Stack Snapshots
- 4 l Label Stack Processing
- 8 t Trace Execution
- 16 o Operator Node Construction
- 32 c String/Numeric Conversions
- 64 P Print Preprocessor Command for -P
- 128 m Memory Allocation
- 256 f Format Processing
- 512 r Regular Expression Parsing
- 1024 x Syntax Tree Dump
- 2048 u Tainting Checks
- 4096 L Memory Leaks (not supported anymore)
- 8192 H Hash Dump -- usurps values()
- 16384 X Scratchpad Allocation
- 32768 D Cleaning Up
+sets debugging flags. To watch how it executes your program, use
+B<-Dtls>. (This works only if debugging is compiled into your
+Perl.) Another nice value is B<-Dx>, which lists your compiled
+syntax tree. And B<-Dr> displays compiled regular expressions;
+the format of the output is explained in L<perldebguts>.
+
+As an alternative, specify a number instead of list of letters (e.g.,
+B<-D14> is equivalent to B<-Dtls>):
+
+ 1 p Tokenizing and parsing
+ 2 s Stack snapshots
+ 4 l Context (loop) stack processing
+ 8 t Trace execution
+ 16 o Method and overloading resolution
+ 32 c String/numeric conversions
+ 64 P Print preprocessor command for -P, source file input state
+ 128 m Memory allocation
+ 256 f Format processing
+ 512 r Regular expression parsing and execution
+ 1024 x Syntax tree dump
+ 2048 u Tainting checks
+ 4096 L Memory leaks (needs -DLEAKTEST when compiling Perl)
+ 8192 H Hash dump -- usurps values()
+ 16384 X Scratchpad allocation
+ 32768 D Cleaning up
+ 65536 S Thread synchronization
+ 131072 T Tokenising
+ 262144 R Include reference counts of dumped variables (eg when using -Ds)
+
+All these flags require B<-DDEBUGGING> when you compile the Perl
+executable. See the F<INSTALL> file in the Perl source distribution
+for how to do this. This flag is automatically set if you include B<-g>
+option when C<Configure> asks you about optimizer/debugger flags.
+
+If you're just trying to get a print out of each line of Perl code
+as it executes, the way that C<sh -x> provides for shell scripts,
+you can't use Perl's B<-D> switch. Instead do this
+
+ # If you have "env" utility
+ env=PERLDB_OPTS="NonStop=1 AutoTrace=1 frame=2" perl -dS program
+
+ # Bourne shell syntax
+ $ PERLDB_OPTS="NonStop=1 AutoTrace=1 frame=2" perl -dS program
+
+ # csh syntax
+ % (setenv PERLDB_OPTS "NonStop=1 AutoTrace=1 frame=2"; perl -dS program)
+
+See L<perldebug> for details and variations.