Hi,
Thanks for the reply.
On Jun 13, 2004, at 3:29 AM, David Cantrell wrote:
Phil Calvert wrote:
I been trying to do "hack no. 8" from the O'Reilly book "Spidering Hacks" but keep getting hung-up.
I enter the line "sudo perl -MCPAN -e 'install libwww-perl'" and things seem to go well for a while but then it gets stuck at:
CPAN: Storable loaded ok
Going to read /Users/thatsme/.cpan/Metadata
Database was generated on Tue, 08 Jun 2004 19:34:06 GMT
Warning: Cannot install 0, don't know what it is.
That's because your perl program (the bit in quotes following the -e) is:
install libwww-perl;
The hyphen is being interpreted as a minus operator. Strings like libwww and perl are interpreted as being zero in numeric context, so that becomes 0 minus 0, which is 0. So you're telling it to install 0.
The fix is to fiddle a bit with the quoting to ensure that libwww-perl is interpreted as one string:
sudo perl -MCPAN -e 'install "libwww-perl"'
As sherm points out, without the extra quotes some modules install just fine, like Foo::Bar. There's no mathemagical operator in there, so perl assumes that you meant it as a string, and so Does The Right Thing.
Ahh, Now I understand! (a little more).
If you'd turned on warnings and strictness like so: perl -MCPAN -Mstrict -Mwarnings -e ... you would have got some rather more useful error messages!
O'Reilly are good at putting errata on their web site, so you really should report this to them. I just checked and it doesn't appear that this one has been reported yet.
-- David Cantrell | Official London Perl Mongers Bad Influence
But when I type in this;
sudo perl -MCPAN -e 'install "libwww-perl"'
I get this;
Password: CPAN: Storable loaded ok Going to read /Users/philcalvert/.cpan/Metadata Database was generated on Sun, 13 Jun 2004 02:36:54 GMT Warning: Cannot install libwww-perl, don't know what it is. Try the command
i /libwww-perl/
to find objects with matching identifiers.
--Phil Calvert Faculty/Staff CSUN Music Dept.
