# Install Perl modules via CPAN

# Installing modules manually

If you don't have permissions to install perl modules, you may still install them manually, indicating a custom path where you've got writing permissions.

Fist, download and unzip module archive:

wget module.tar.gz
tar -xzf module.tar.gz
cd module

Then, if the module distribution contains a Makefile.PL file, run:

perl Makefile.PL INSTALL_BASE=$HOME/perl
make
make test
make install

or if you have Build.PL file instead of a Makefile.PL:

perl Build.PL --install_base $HOME/perl
perl Build
perl Build test
perl Build install

You also have to include the module path in PERL5LIB environment variable in order to use it in your code:

export PERL5LIB=$HOME/perl

# cpanminus, the lightweight configuration-free replacement for cpan

Usage

To install a module (assuming cpanm is already installed):

cpanm Data::Section

cpanm ("cpanminus") strives to be less verbose than cpan but still captures all of the installation information in a log file in case it is needed. It also handles many "interactive questions" for you, whereas cpan doesn't.

cpanm is also popular for installing dependencies of a project from, e.g., GitHub. Typical use is to first cd into the project's root, then run

cpanm --installdeps .

With --installdeps it will:

  • Scan and install **configure_requires** dependencies from either
      1. META.json 1. META.yml (if META.json is missing)
  • 1. Build the project (equivalent to `perl Build.PL`), generating MYMETA files
  • Scan and install **requires** dependencies from either
      1. MYMETA.json 1. MYMETA.yml (if MYMETA.json is missing)
    • MYMETA.json
    • MYMETA.yml (if MYMETA.json is missing)

    To specify the file 'some.cpanfile', containing the dependencies, run:

    cpanm --installdeps --cpanfile some.cpanfile .
    
    

    cpanm Installation

    There are several ways to install it. Here's installation via cpan:

    cpan App::cpanminus
    
    

    cpanm Configuration

    There is no config file for cpanm. Rather, it relies on the following environment variables for its configuration:

  • `PERL_CPANM_OPT` (General cpanm command line options)
      - `export PERL_CPANM_OPT="--prompt"` # in .bashrc, to enable prompting, e.g. - `setenv PERL_CPANM_OPT "--prompt"` # in .tcshrc

      # Run Perl CPAN in your terminal (Mac and Linux) or command prompt (Windows)

      # Command line

      You can use cpan to install modules directly from the command line:

      cpan install DBI
      
      

      This would be followed by possibly many pages of output describing exactly what it is doing to install the module. Depending on the modules being installed, it may pause and ask you questions.

      # Interactive Shell

      You can also enter a "shell" thus:

      perl -MCPAN -e "shell"
      
      

      It will produce output as below:

      Terminal does not support AddHistory.
      
      cpan shell -- CPAN exploration and modules installation (v2.00)
      Enter 'h' for help.
      
      cpan[1]>
      
      

      Then you can install the modules which you want by the easy command install <module>.

      Example: cpan[1]> install DBI

      After installing successfully, type exit to quit.