more install.sh

[Julian Field]

Rick Cooper wrote:
>  
>
>  > -----Original Message-----
>  > From: mailscanner-bounces at lists.mailscanner.info 
>  > [mailto:mailscanner-bounces at lists.mailscanner.info] On 
>  > Behalf Of Julian Field
>  > Sent: Tuesday, October 21, 2008 9:31 AM
>  > To: MailScanner discussion
>  > Subject: Re: more install.sh
>  > 
>  > 
>  > 
>  > Mark Nienberg wrote:
>  > > I think on a centOS system the installer.sh is doing this 
>  > for the perl 
>  > > modules that conflict with the base perl:
>  > >
>  > > check to see if the perl module is installed,
>  > > see that it isn't,
>  > > build an rpm for the module from the downloaded src,
>  > > attempt to install the rpm, but the install fails due to 
>  > conflict with 
>  > > installed perl,
>  > > force install only for those that absolutely need it.
>  > >
> [...]
>  > part of the 
>  > > the core perl installation? I suspect that must not be possible or 
>  > > Jules would have done it already.
>  > Not easy. You can't find where a Perl module is installed, 
>  > just that it 
>  > *is* installed.
>
> Try perldoc -T perllocal. Outputs all modules that are installed in the
> following format:
>
>
>   Mon Sep  8 12:53:02 2008: "Module" DBI::Shell
>     *   "installed into: /usr/lib/perl5/site_perl/5.8.8"
>
>     *   "LINKTYPE: dynamic"
>
>     *   "VERSION: 11.95"
>
>     *   "EXE_FILES: dbish"
>
> Not hard to parse, gives location (if that is really important) and version
> (where available). If you didn't want to return all modules and parse for
> the ones you want then
>
> cls;perldoc -t perllocal |grep -A 7 DBI::Shell
>
> Would return the above but only the one module DBI::Shell. Since you are
> using a shell script I suppose you would have to do a loop and something
> like
>
> MODULE=`perldoc -t perllocal |grep -A 7 DBI::Shell|grep '"Module"'|sed
> 's/.*Module" //'`
> VERSION=`perldoc -t perllocal |grep -A 7 DBI::Shell|grep 'VERSION'|sed
> 's/.*VERSION: //'|sed 's/"//g'`
> LOCATION=`perldoc -t perllocal |grep -A 7 DBI::Shell|grep 'installed
> into'|sed 's/.*into: //'|sed 's/"//g'`
>
> Or better yet run the perldoc -t perllocal > tempfile.name
>
> And grep tempfile.name for the information so the call to perldoc would only
> be used once for speed.
>
>  > >
>  > > Also, the installer builds rpms for packages that will not 
>  > install due 
>  > > to already installed rpms.  For example, on my system it builds
>  > > perl-IO-stringy-2.110-1
>  > > and tries to install it, but discovers that
>  > > perl-IO-stringy-2.110-1.2.el5.rf
>  > > is already installed.
>  > >
>  > > Could the installer test for already installed rpms before 
>  > building 
>  > > and attempting installation of the new one?
>  > > In the above example it would run "rpm -q perl-IO-stringy" 
>  > and then do 
>  > > some sort of version checking.
>  > The version checking you need to do is far from trivial. 
>  > 2.10 is greater 
>  > than 2.9, but not in numerical or alphabetical terms. It's quite a 
>  > tricky problem. I really don't want to open that Pandora's box! :-)
>  > 
>  > Nice ideas though...
> [...]
>
> If you are just comparing parsed version numbers why not do the following
> with the above example (scale 7 should cover the weird 0.10789 versions)
>
>  echo "scale=7;2.10 >= 2.9"|bc
>
> Which would output 0 but
> echo 'scale=7;2.10 <= 2.9' |bc
>
> Would output 1
>   
Well, yes, but that's not so much use when:
scale=7
2.10 <= 2.9
1
2.8 <= 2.9
1

Obviously 2.1 (as a number) is less than 2.9, I need it to be able to 
tell that 2.10 (as a version number two point ten) > two point nine.
> Of course you would have to make sure that MODULE|VERSION != '' and install
> as required but that is trivial
>
> Rick
>
>
> --
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>
>   

Jules

-- 
Julian Field MEng CITP CEng
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