Devel::Trace - Print out each line before it is executed (like sh -x)
sh -x
perl -d:Trace program
If you run your program with perl -d:Trace program, this module will print a message to standard error just before each line is executed. For example, if your program looks like this:
#!/usr/bin/perl print "Statement 1 at line 4\n"; print "Statement 2 at line 5\n"; print "Call to sub x returns ", &x(), " at line 6.\n"; exit 0; sub x { print "In sub x at line 12.\n"; return 13; }
Then the Trace output will look like this:
Trace
>> ./test:4: print "Statement 1 at line 4\n"; >> ./test:5: print "Statement 2 at line 5\n"; >> ./test:6: print "Call to sub x returns ", &x(), " at line 6.\n"; >> ./test:12: print "In sub x at line 12.\n"; >> ./test:13: return 13; >> ./test:8: exit 0;
This is something like the shell's -x option.
-x
Inside your program, you can enable and disable tracing by doing
$Devel::Trace::TRACE = 1; # Enable $Devel::Trace::TRACE = 0; # Disable
or
Devel::Trace::trace('on'); # Enable Devel::Trace::trace('off'); # Disable
Devel::Trace exports the trace function if you ask it to:
Devel::Trace
trace
import Devel::Trace 'trace';
Then if you want you just say
trace 'on'; # Enable trace 'off'; # Disable
You should be able to send the trace output to the filehandle of your choice.
You should be able to specify the format of the output.
You should be able to get the output into a string.
We'll see.
Devel::Trace 0.11 and its source code are hereby placed in the public domain.
To install Devel::Trace, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Devel::Trace
CPAN shell
perl -MCPAN -e shell install Devel::Trace
For more information on module installation, please visit the detailed CPAN module installation guide.