Get started developing with Perl 5.20 from Red Hat Software Collections in under 10 minutes.
In this tutorial, you will set your system up to install software from Red Hat Software Collections (RHSCL), which provides the latest development technologies for Red Hat Enterprise Linux. Then, you will install Perl 5.20 and run a simple “Hello, World” application. The whole tutorial should take less than ten minutes to complete.
You will need a Red Hat Enterprise Linux 6 system with a current Red Hat subscription that allows you to download software and updates from Red Hat. Access to the Red Hat Software Collections (RHSCL) is included with many Red Hat Enterprise Linux (RHEL) subscriptions. For more information about which subscriptions include RHSCL, see How to use Red Hat Software Collections (RHSCL) or Red Hat Developer Toolset (DTS).
If you don’t have a Red Hat Enterprise Linux subscription, you can try it for free. Get started with an evaluation at https://access.redhat.com/products/red-hat-enterprise-linux/evaluation. Select the Red Hat Enterprise Linux Developer Workstation option to ensure your evaluation will include both RHSCL and DTS.
If you encounter difficulties at any point, see Troubleshooting and FAQ.
In this step you will configure your system to obtain software, including the latest dynamic languages, from the RHSCL software repository. Instructions are provided for both the command line (CLI) and graphical user interface (GUI).
Note: If your system uses Red Hat Network (RHN) Classic instead of Red Hat Subscription Management (RHSM) for managing subscriptions and entitlements, please skip this step and follow the Installation chapter of the Red Hat Software Collections 2.0 Release Notes. The instructions in this section are only for systems using RHSM. The remainder of this tutorial applies to systems running either RHSM or RHN Classic.
Red Hat Subscription Manager can be started from the System → Administration subgroup of the Applications menu. Alternatively, you can start it from the command prompt by typing subscription-manager-gui.
Select Repositories from the System menu of the subscription manager. In the list of repositories, check the Enabled column for rhel-server-rhscl-6-rpms and rhel-6-server-optional-rpms. If you are using a desktop version of Red Hat Enterprise Linux, the repositories will be named rhel-desktop-rhscl-6-rpms and rhel-6-desktop-optional-rpms.
If you don’t see any RHSCL repositories in the list, your subscription might not include it.
See Troubleshooting and FAQ for more information.
You can add or remove software repositories from the command line using the subscription-manager tool as the root user. Use the --list option to view the available software repositories and verify that you have access to RHSCL:
$ su -
# subscription-manager repos --list | egrep rhsclIf you don’t see any RHSCL repositories in the list, your subscription might not include it. See Troubleshooting and FAQ for more information.
If you are using a desktop edition of Red Hat Enterprise Linux, change -server- to -desktop- in the following commands:
# subscription-manager repos --enable rhel-server-rhscl-6-rpms
# subscription-manager repos --enable rhel-6-server-optional-rpmsIn this next step you will install Perl 5.20 from RHSCL:
$ su -
# yum install rh-perl520If you need help, see Troubleshooting and FAQ.
Under your normal user ID, start a Terminal window. First, use scl enable to add Perl 5.20 to your environment. Then run perl -v to check the version number.
$ scl enable rh-perl520 bash
$ perl -v
This is perl 5, version 20, subversion 1 (v5.20.1)The next step is to create a Perl program that can be run from the command line. Using your preferred text editor, create a file named hello.pl:
$ nano hello.pl
Add the following text to the file:
#!/usr/bin/env perl
#
print "Hello, Red Hat Developers World from Perl $^V\n";Save it and exit the editor. Then make the script executable and run it:
$ chmod +x hello.pl
$ ./hello.pl
Hello, Red Hat Developers World from Perl v5.20.1If you get the error: perl command not found, or see an older version number, you need to run scl enable rh-perl520 bash first.
The software packages in RHSCL are designed to allow multiple versions of software to be installed concurrently. To accomplish this, the desired package is added to your runtime environment as needed with the scl enable command. When scl enable runs, it modifies environment variables and then runs the specified command. The environmental changes only affect the command that is run by scl and any processes that are run from that command. The steps in this tutorial run the command bash to start a new interactive shell to work in the updated environment. The changes aren’t permanent. Typing exit will return to the original shell with the original environment. Each time you login, or start a new terminal sesssion, scl enable needs to be run again.
While it is possible to change the system profile to make RHSCL packages part of the system’s global environment, this is not recommended. Doing this can cause conflicts and unexpected problems with other applications because the system version of the package is obscured by having the RHSCL version in the path first.
To make one or more RHSCL packages a permanent part of your development environment, you can add it to the login script for your specific user ID. this is the recommend approach for development as only processes run under your user ID will be affected.
Using your preferred text editor, add the following line to ~/.bashrc:
source scl_source enable rh-perl520
After making the change, you should log out and log back in again.
When you deliver an application that uses RHSCL packages, a best practice is to have your startup script handle the scl enable step for your application. You should not ask your users to change their environment as this is likely to create conflicts with other applications.
Read Perl Tutorials at learn.perl.org
http://learn.perl.org/tutorials/
Find additional Perl components
$ yum list available rh-perl520-\*
View the list of software available in RHSCL
$ yum --disablerepo="*" --enablerepo="rhel-server-rhscl-6-rpms" list available
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How to use Red Hat Software Collections (RHSCL) or Red Hat Developer Toolset (DTS)
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Red Hat Software Collection 2.0 Documentation
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Red Hat Software Collections 2.0 Packaging Guide
Developers should read this guide to get a more complete understanding of how software collections work, and how to deliver software that uses RHSCL.
Red Hat delivers the resources and ecosystem of experts to help you be more productive and build great solutions. Register for free at developers.redhat.com.
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The RHSCL repository is not available or is not found on my system.
The name of the repository depends on whether you have a server or desktop version of Red Hat Enterprise Linux installed.
Some Red Hat Enterprise Linux subscriptions do not include access to RHSCL. See How to use Red Hat Software Collections (RHSCL) or Red Hat Developer Toolset (DTS).
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yum install fails due to a missing dependency.
These packages are in the optional RPMs repository, which is not enabled by default. See [Enable Red Hat Software Collections] for how to enable both the optional RPMs and RHSCL repositories.
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How can I find out what RHSCL packages are installed?
scl --listwill show the list of RHSCL packages that have been installed, whether they are enabled or not.$ scl --list rh-perl520 rh-php56 rh-python34 rh-ruby22 -
How do I find out if there is a newer version of Perl in the RHSCL?
How do I find out what version of Perl is available in the RHSCL?
I have the RHSCL repository enabled, but I can’t find the Perl version listed in this tutorial?
Use the following command to find packages with matching names:
# yum list available rh-perl\* -
I’ve installed Perl 5.20 from RHSCL, but it is not in my path.
RHSCL does not alter the system path. You need to use `scl enabl`e to change the environment for your session:
$ scl enable rh-perl520 bashFor more information see the Red Hat Software Collection 2.0 Documentation.
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When I try to run Perl, I get an error about a missing shared library.
This is due to not having run
scl enablefirst. Whenscl enableruns, in addition to setting up the command search PATH, it also sets up the search path for shared libraries, LD_LIBRARY_PATH.