perlbug - how to submit bug reports on Perl


perlbug [ -v ] [ -a address ] [ -s subject ]
[ -b body | -f inputfile ] [ -F outputfile ]
[ -r returnaddress ] [ -e editor ]
[ -c adminaddress | -C ] [ -S ] [ -t ]  [ -d ]  [ -h ]

perlbug [ -v ] [ -r returnaddress ]
[ -ok | -okay | -nok | -nokay ]


A program to help generate bug reports about perl or the modules that come with it, and mail them.

If you have found a bug with a non-standard port (one that was not part of the standard distribution), a binary distribution, or a non-standard module (such as Tk, and CGI), please see the documentation that came with that distribution to determine the correct place to report bugs.

The perlbug(1) utility is designed to be used interactively. Normally no arguments will be needed. Simply run it and follow the prompts.

If you are unable to run perlbug(1) (most likely because you do not have a working setup to send mail that perlbug(1) recognizes), you might have to compose your own report, and email it to In such a case, you might find the -d option useful to get summary information.

Whenever reporting a bug, please include answers to the following questions:

Which version of perl are you running?
If you do not know which version you are running, type perl -v at the command line.
Are you running the most recently released version of perl?

To determine this, go to the Perl Web site at If you are not running the most recently released version, get the most recent version and determine whether your bug has been fixed. Note that bug reports about old versions of perl, especially those prior to the 5.0 release, are likely to fall upon deaf ears. You are on your own if you continue to use perl1 .. perl4.

Are you sure what you have is a bug?
A significant number of the bug reports we get turn out to be documented features in perl. Make sure the behavior you are witnessing does not fall under that category, by glancing through the documentation that comes with perl.

Be aware of the familiar traps that perl programmers of various hues fall into. See perltrap.

Check in perldiag to see what any perl error message means. If the message is not in perldiag, it probably is not generated by perl, and you should consult your operating system documentation.

If you are on a non-UNIX platform check also the perlport; some features might not be implemented or might work differently.

Try to study the problem under the perl debugger, if necessary. See perldebug.

Do you have a proper test case?
The easier it is to reproduce your bug, the more likely it will be fixed, because if no one can duplicate the problem, no one can fix it. A good test case has most of these attributes: fewest possible number of lines; few dependencies on external commands, modules, or libraries; runs on most platforms unimpeded; and is self-documenting.

A good test case is almost always a good candidate to be on the perl test suite. If you have the time, consider making your test case so that it will readily fit into the standard test suite.

Remember to include the exact error messages, if any. "Perl complained something" is not an exact error message.

If you get a core dump (or equivalent), you can use a debugger (such as dbx or gdb) to produce a stack trace to include in the bug report. NOTE: unless your Perl has been compiled with debug info (often -g), the stack trace is likely to be somewhat difficult to use because it will probably contain only the function names, not their arguments. If possible, recompile your Perl with debug info and reproduce the dump and the stack trace.

Can you describe the bug in plain English?

The easier it is to understand a reproducible bug, the more likely it will be fixed. Anything you can provide by way of insight into the problem helps a great deal. In other words, try to analyze the problem to the extent you feel qualified and report your discoveries.

Can you fix the bug yourself?
A bug report which includes a patch to fix it will almost definitely be fixed. Use the diff(1) program to generate your patches (diff(1) is being maintained by the GNU folks as part of the diffutils package, so you should be able to get it from any of the GNU software repositories). If you do submit a patch, the cool-dude counter at will register you as a savior of the world. Your patch may be returned with requests for changes, or requests for more detailed explanations about your fix.

Here are some clues for creating quality patches: Use the -c or -u switches to the diff program (to create aso-called context or unified diff). Make sure the patch is not reversed (the first argument to diff is typically the original file, the second argument your changed file). Make sure you test your patch by applying it with the patch program before you send it on its way. Try to follow the same style as the code you are trying to patch. Make sure your patch really does work (make test, if the thing you're patching supports it).

Can you use perlbug(1) to submit the report?
Among other things,

perlbug(1) will ensure your report includes crucial information about your version of perl. If perlbug(1) is unable to mail your report after you have typed it in, you might have to compose the message yourself, add the output produced by perlbug -d and email it to If, for some reason, you cannot run perlbug at all on your system, be sure to include the entire output produced by running perl -V (note the uppercase V).

Whether you use perlbug(1) or send the email manually, please make your subject informative. Comments like "a bug" are not informative. Neither are "perl crashes" or "HELP!!!," these all are null information. A compact description of what is wrong is fine.

Having done your bit, please be prepared to wait, to be told the bug is in your code, or even to get no reply at all. The perl maintainers are busy folks, so if your problem is a small one or if it is difficult to understand or already known, they might not respond with a personal reply. If it is important to you that your bug be fixed, monitor the "Changes" file in any development releases that have occurred since the time you submitted the bug, and encourage the maintainers with kind words (but never any flames!). Feel free to resend your bug report if the next released version of perl comes out and your bug is still present.


Address to send the report to. Defaults to
Body of the report. If not included on the command line or in a file with -f, you will get a chance to edit the message.
Do not send copy to administrator.
Address to which copy of report should be sent. Defaults to the address of the local perl administrator (recorded when perl was built).
Data mode (the default if you redirect or pipe output). This prints out your configuration data, without mailing anything. You can use this with -v to get more complete data.
Editor to use.
File containing the body of the report. Use this to send a prepared message quickly.
File to output the results to instead of sending as an email. Useful when running perlbug(1) on a computer with no direct Internet connection.
Prints a brief summary of the options.
Report successful build on this system to perl porters. Forces -S and -C. Forces and supplies values for -s and -b. Only prompts for a return address if it cannot guess it (for use with make(1)). Honors return address specified with -r. You can use this with -v to get more complete data. Only makes a report if this system is less than 60 days old.
As -ok except it will report on older systems.
Report unsuccessful build on this system. Forces -C. Forces and supplies a value for -s, then requires you to edit the report and explain what went wrong. Alternatively, a prepared report might be supplied using -f. Only prompts for a return address if it cannot guess it (for use with make(1)). Honors return address specified with -r. You can use this with -v to get more complete data. Only makes a report if this system is less than 60 days old.
As -nok except it will report on older systems.
Your return address. The program will ask you to confirm its default if you do not use this option.
Send without asking for confirmation.
Subject to include with the message. You will be prompted if you do not supply one on the command line.
Test mode. The target address defaults to
Include verbose configuration data in the report.


Kenneth Albanowski. Subsequently doctored by Gurusamy Sarathy, Tom Christiansen, Nathan Torkington, Charles F. Randall, Mike Guy, Dominic Dunlop, Hugo van der Sanden, and Jarkko Hietaniemi.