perlplan9 - Plan 9-specific documentation for Perl


These are a few notes describing features peculiar to Plan 9 Perl. As such, it is not intended to be a replacement for the rest of the Perl 5 documentation (which is both copious and excellent). If you have any questions to which you can't find answers in these man pages, contact Luther Huffman at and we'll try to answer them.

Invoking Perl

Perl is invoked from the command line as described in the perl manpage. Most perl scripts, however, do have a first line such as ``#!/usr/local/bin/perl''. This is known as a shebang (shell-bang) statement and tells the OS shell where to find the perl interpreter. In Plan 9 Perl this statement should be ``#!/bin/perl'' if you wish to be able to directly invoke the script by its name. Alternatively, you may invoke perl with the command ``Perl'' instead of ``perl''. This will produce Acme-friendly error messages of the form ``filename:18''.

Some scripts, usually identified with a *.PL extension, are self-configuring and are able to correctly create their own shebang path from config information located in Plan 9 Perl. These you won't need to be worried about.

What's in Plan 9 Perl

Although Plan 9 Perl currently only provides static loading, it is built with a number of useful extensions. These include Opcode, FileHandle, Fcntl, and POSIX. Expect to see others (and DynaLoading!) in the future.

What's not in Plan 9 Perl

As mentioned previously, dynamic loading isn't currently available nor is MakeMaker. Both are high-priority items.

Perl5 Functions not currently supported

Some, such as chown and umask aren't provided because the concept does not exist within Plan 9. Others, such as some of the socket-related functions, simply haven't been written yet. Many in the latter category may be supported in the future.

The functions not currently implemented include:

    chown, chroot, dbmclose, dbmopen, getsockopt, 
    setsockopt, recvmsg, sendmsg, getnetbyname, 
    getnetbyaddr, getnetent, getprotoent, getservent, 
    sethostent, setnetent, setprotoent, setservent, 
    endservent, endnetent, endprotoent, umask

There may be several other functions that have undefined behavior so this list shouldn't be considered complete.


For compatibility with perl scripts written for the Unix environment, Plan 9 Perl uses the POSIX signal emulation provided in Plan 9's ANSI POSIX Environment (APE). Signal stacking isn't supported. The signals provided are:



``As many as there are grains of sand on all the beaches of the world . . .'' - Carl Sagan

Revision date

This document was revised 09-October-1996 for Perl 5.003_7.


Luther Huffman,


We are painfully aware that these documents may contain incorrect links and misformatted HTML. Such bugs lie in the automatic translation process that automatically created the hundreds and hundreds of separate documents that you find here. Please do not report link or formatting bugs, because we cannot fix per-document problems. The only bug reports that will help us are those that supply working patches to the installhtml or pod2html programs, or to the Pod::HTML module itself, for which I and the entire Perl community will shower you with thanks and praises.

If rather than formatting bugs, you encounter substantive content errors in these documents, such as mistakes in the explanations or code, please use the perlbug utility included with the Perl distribution.

--Tom Christiansen, Perl Documentation Compiler and Editor

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