1. mkdir /custom/perl/
2. cd /custom/perl/
3. curl -O http://www.cpan.org/src/perl-5.12.3.tar.gz
4. mkdir perl-5_12_3
5. gunzip perl-5.12.3.tar.gz
6. tar -xf perl-5.12.3.tar
7. cd perl-5.12.3
8. ./Configure -d -Dprefix=/custom/perl/perl-5_12_3
9. make
10. make test
11. make install
12. /custom/perl/perl-5_12_3/bin/perl -v
13. /custom/perl/perl-5_12_3/bin/perl -e ‘print “hello world.\n”;’
14. /custom/perl/perl-5_12_3/bin/perl -MCPAN -e shell
    • Auto configure as much as possible. Step 15 will edit it.
15. Edit /custom/perl/perl-5_12_3/lib/5.12.3/CPAN/Config.pm
    • Change the following paths:
    • ‘cpan_home’ => q[/custom/perl/perl-5_12_3/cpan/],
    • ‘build_dir’ => q[/custom/perl/perl-5_12_3/cpan/build],
    • ‘histfile’ => q[/custom/perl/perl-5_12_3/cpan/histfile],
    • ‘keep_source_where’ => q[/custom/perl/perl-5_12_3/cpan/sources],
    • ”prefs_dir’ => q[/custom/perl/perl-5_12_3/cpan/prefs],
    • ”urllist’ => [q[ftp://my.cpan.mirror/pub/cpan/]],
16. Run CPAN and install Bundle::CPAN Bundle::LWP and any required packages
17. tar -cvf /custom/perl/custom-perl5.12.13.tar /custom/perl/perl-5_12_3/*
18. gzip /custom/perl/custom-perl5.12.13.tar
19. Ship custom-perl5.12.13.tar.gz out to your matching architectures or mount it on a shared NAS.
20. Call it with #!/custom/perl/perl-5_12_3/bin/perl

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What we’re doing in a nutshell is telling PERL to push values on to the @INC array before loading any modules. You can do this on the command line, in your PERL code or with the environment variable PERL5LIB.

PERL5LIB can contain more than one value. Just set it in you .bashrc file or wherever you see fit. This method works in bash:

export PERL5LIB=/first/path/to/libs"${PERL5LIB:+:$PERL5LIB}"
export PERL5LIB=/second/path/to/libs"${PERL5LIB:+:$PERL5LIB}"
export PERL5LIB=/third/path/to/libs"${PERL5LIB:+:$PERL5LIB}"

You can check what PERL is going to use by printing out the contents of @INC. You can print an array without a loop using join() as I blogged about before:

perl -e 'print join "\n", @INC;'

Let’s put it together:
~$ perl -e 'print join "\n", @INC;'
/etc/perl
/usr/local/lib/perl/5.10.0
/usr/local/share/perl/5.10.0
/usr/lib/perl5
/usr/share/perl5
/usr/lib/perl/5.10
/usr/share/perl/5.10
/usr/local/lib/site_perl
.

~$ env|grep -i perl
~$

~$ export PERL5LIB=/first/path/to/libs"${PERL5LIB:+:$PERL5LIB}"
~$ export PERL5LIB=/second/path/to/libs"${PERL5LIB:+:$PERL5LIB}"
~$ export PERL5LIB=/third/path/to/libs"${PERL5LIB:+:$PERL5LIB}"

~$ env|grep -i perl
PERL5LIB=/third/path/to/libs:/second/path/to/libs:/first/path/to/libs

~$ perl -e 'print join "\n", @INC;'
/third/path/to/libs
/second/path/to/libs
/first/path/to/libs
/etc/perl
/usr/local/lib/perl/5.10.0
/usr/local/share/perl/5.10.0
/usr/lib/perl5
/usr/share/perl5
/usr/lib/perl/5.10
/usr/share/perl/5.10
/usr/local/lib/site_perl
.

And there it is. Your PERL apps will look in those locations starting from the top.

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if((getpwuid($<) eq "root") || ($< == 0)){
print STDOUT "Cannot run as root!\n";
exit(1);
}

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join EXPR,LIST
Joins the separate strings of LIST into a single string with fields separated by the value of EXPR, and returns that new string. Example:
$rec = join(':', $login,$passwd,$uid,$gid,$gcos,$home,$shell);

From the code example, you can make CSV output and all kinds of goodies, but what the doc misses and the example doesn’t show is that combining join() with a print statement makes writing lists to STDOUT or a file handle a snap. This is where join() really shines.

Example:

Code
@names = ('Mark', 'Jim', 'Bob','Mary','Steven','Gomer');
print join("\n", @names);

Output
Mark
Jim
Bob
Mary
Steven
Gomer

Note that this will NOT print a final or beginning string. Join() concatenates the elements, meaning it puts the string value BETWEEN the list elements.

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Will give you:

$VAR1 = {
'key2' => 'value2',
'key1' => 'value1'
};
$VAR2 = {
'key2' => 'value2',
'key1' => 'value1'
};
$VAR3 = {
'key2' => 'value2',
'key1' => 'value1'
};


Snazzy!

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