Invoking Perl¶

Perl is invoked from the command line as described in perl. 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 in Plan 9 Perl¶

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.

Signals in Plan 9 Perl¶

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:

    SIGHUP, SIGINT, SIGQUIT, SIGILL, SIGABRT,
    SIGFPE, SIGKILL, SIGSEGV, SIGPIPE, SIGPIPE, SIGALRM, 
    SIGTERM, SIGUSR1, SIGUSR2, SIGCHLD, SIGCONT,
    SIGSTOP, SIGTSTP, SIGTTIN, SIGTTOU

Installing Perl Documentation on Plan 9¶

This perl distribution comes with a tremendous amount of documentation. To add these to the built-in manuals that come with Plan 9, from /sys/src/cmd/perl/5.00301 (adjust version appropriately) run:

        mk man

To begin your reading, start with:

        man perl

This is a good introduction and will direct you towards other man pages that may interest you.

(Note: "mk man" may produce some extraneous noise. Fear not.)