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I've grown accustomed to ruby having poorly accessible documentation. What I mean by 'poorly accessible' is the fact that ri Array gives me a list of things Array can do (which is nice), but to actually find out about Array.delete I have to run ri Array.delete. I got used to Python's often-helpful ways of pydoc showing you what appears to be "as much as possible" when you pydoc a class, module, or method.

Maybe I'm doing it wrong. Either way, the following is annoying and unhelpful. While it tells me the arguments that should be passed, and what is returned, it doesn't help me really know more about the function. Luckly, I'm already familiar with select from other languages.

snack(~) % ri IO.select
------------------------------------------------------------- IO::select
     IO.select(read_array 
     [, write_array 
     [, error_array 
     [, timeout]]] ) =>  array  or  nil
------------------------------------------------------------------------
     See +Kernel#select+.

Ok, fine... Let's look at Kernel#select.

snack(~) % ri Kernel#select
---------------------------------------------------------- Kernel#select
     IO.select(read_array 
     [, write_array 
     [, error_array 
     [, timeout]]] ) =>  array  or  nil
------------------------------------------------------------------------
     See +Kernel#select+.

*sigh*

This is a guest post written by SathiyaMoorthy.

This article is part of the ongoing Vi / Vim Tips and Tricks Series. As a programmer, you may do lot of repetitive tasks while coding such as:

• Adding file header
• Adding function/frame comment
• Including default code snippet
• Performing syntax check
• Reading documentation about a function
• Converting a code block to comment, and vice versa

The Perl-Support Vim Plugin - Perl-IDE offers easiest way to do all of the above, saving lot of time and keystrokes.

The plugin was written by Fritz Mehner, who explains the purpose of the plugin as: “Write and run Perl-scripts using menus and hot keys”.

This article explains how to install the plugin in 3 easy steps and 7 powerful features of the plugin.

3 Steps to Install the Perl-Support Vim Plugin

Step 1: Download Perl-Support Vim Plugin

Download the plugin from vim.org website.

$ cd /usr/src
$ wget http://www.vim.org/scripts/download_script.php?src_id=9701

Step 2: Install the Perl-Support Vim Plugin

$ mkdir ~/.vim
$ cd ~/.vim
$ unzip /usr/src/perl-support.zip

Step 3: Enable the plugin in the ~/.vimrc

Add the following line to the ~/.vimrc to enable the plugin for Vim editor.

$ vim ~/.vimrc
filetype plugin on

7 Powerful Features of Perl-Support Vim Plugin

Feature 1: Add Automatic Header to *.pl file

When you open a file with the extension .pl it opens the file with header as shown below. This will also place the cursor in the Description field in Insert mode.

$ vim myprogram.pl
#!/usr/bin/perl
#===================================================
#
#         FILE:  myprogram.pl
#
#        USAGE:  ./myprogram.pl
#
#  DESCRIPTION:
#
#      OPTIONS:  ---
# REQUIREMENTS:  ---
#         BUGS:  ---
#        NOTES:  ---
#       AUTHOR:  Dr. Fritz Mehner (mn), mehner@fh-swf.de
#      COMPANY:  FH Südwestfalen, Iserlohn
#      VERSION:  1.0
#      CREATED:  12/23/2008 03:47:07 PM
#     REVISION:  ---
#===================================================

use strict;
use warnings;

To change the default value of the AUTHOR and COMPANY, modify the default value in ~/.vim/perl-support/templates/Templates

$ vim ~/.vim/perl-support/templates/Templates
|AUTHOR|    = SathiyaMoorthy
|AUTHORREF| = sm
|EMAIL|     = test@test.com
|COMPANY|   = mycompany

Now, when you create a new perl file, it will show the modified values for AUTHOR and COMPANY as shown below.

$ vim myprogram.pl
#!/usr/bin/perl
#===================================================
#
#         FILE:  myprogram.pl
#
#        USAGE:  ./myprogram.pl
#
#  DESCRIPTION:
#
#      OPTIONS:  ---
# REQUIREMENTS:  ---
#         BUGS:  ---
#        NOTES:  ---
#       AUTHOR:  SathiyaMoorthy (sm), test@test.com
#      COMPANY:  mycompany
#      VERSION:  1.0
#      CREATED:  12/23/2008 04:09:23 PM
#     REVISION:  ---
#===================================================

use strict;
use warnings;

Note: To add custom fields to the header, modify the ~/.vim/perl-support/templates/file-description.template file and add your own custom field.

Feature 2: Adding Perl Subroutine using \isu

For writing a subroutine, type \isu in normal mode, which will prompt for the subroutine name (as shown in Fig1 below) and inserts the subroutine with default function content (as shown in Fig2 below).

Feature 3: Insert a Function Header using \cfu

For inserting a function header, type \cfu in normal mode, which will add the comment as shown below.

Feature 4: Add a Frame comment using \cfr

To add a frame comment, type \cfr in normal mode, which will give the following formatted comment.

Feature 5: Save the file and execute it immediately using \rr

Type \rr in the normal mode, which will save the file and execute it immediately.

Feature 6: Comment a block of code using \cc

To change a entire code block to comment, select the code in visual mode and type \cc.

Feature 7: Insert pre-defined code-snippet to the Perl code using \nr

The plugin comes with few pre-defined code snippets that you can insert into your code. Following are the default code snippets that comes with the plugin.

$ ls ~/.vim/perl-support/codesnippets/
dot.SmallProf                print-data-structure-with-Dumper.pl
free-software-comment        print-hash.pl
inside-out-class.pl          print-hash-sorted.pl
module-interface.pl          process-all-files-in-a-directory-recursively.pl
new.pl                       slurp-file.pl
pod-template-application.pl  SmallProf-variables.pl
pod-template-module.pl

For example, if you want to create a function that will print the hash values, you can re-use it from the existing code snippets. Following is the content of the print-hash.pl pre-defined code snippets.

$ cat ~/.vim/perl-support/codesnippets/print-hash.pl

#----------------------------------------------------------------------
#  subroutine : print_hash
#----------------------------------------------------------------------
sub print_hash {
  my  $hashref  = shift;      # 1. parameter : hash reference
  print "\n";
  while ( my ( $key, $value ) = each %$hashref ) {
    print "'$key'\t=>\t'$value'\n";
  }       # -----  end while  -----
} # ----------  end of subroutine print_hash_sorted  ----------

To insert this into your working perl program, type \nr from the normal mode inside vim, which will prompt “read snippet /home/rnatarajan/.vim/perl-support/codesnippets/”, type print-hash.pl at the end and press enter, which will insert the content of the ~/.vim/perl-support/codesnippets/print-hash.pl to your working file automatically.

Note: You can define your own code snippets and place it under ~/.vim/perl-support/codesnippets/. You can also build your own code snippets from the existing code - select the part of code need to be made as code snippet, press \nw, and give a file-name to it. From next time, type \nr and the file-name to get your custom code snippet.

There are lot of powerful features in the PerlSupport Vim Plugin. Read the documentation for more information. The documentation is located in the following location on your system.

• README : ~/.vim/README.perlsupport
• PDF : ~/.vim/perl-support/doc/perl-hot-keys.pdf
• Online perl-support vim plugin documentation

This article is part of the ongoing Vi / Vim Tips and Tricks series. Please subscribe to TheGeekStuff and don’t miss any future Vi and Vim editor tips and tricks.


This article was written by SathiyaMoorthy, developer of EPQA. Sathiya got impressed by the 15 Examples To Master Linux Command Line History article on this blog and became a regular reader and contributor. The Geek Stuff welcomes your tips and guest articles.

Post from: The Geek Stuff

Make Vim as Your Perl IDE Using perl-support.vim Plugin

I spent some time yesterday making backups of things I care about (code, content here, etc) in two remote places, in case anything should happen. Now two places are copying down data for me every few days. Backups are easy to ignore, but critical when you lose data.

Today, I heard about journalspace going down because it lost data and didn't have backups. While I don't use the service, so it doesn't affect me, the failure they experienced makes for a great case study in false data security and backups. From the front page of journalspace.com:

Here is what happened: the server which held the journalspace data had two large drives in a RAID configuration. As data is written (such as saving an item to the database), it's automatically copied to both drives, as a backup mechanism.

The value of such a setup is that if one drive fails, the server keeps running, using the remaining drive. Since the remaining drive has a copy of the data on the other drive, the data is intact. The administrator simply replaces the drive that's gone bad, and the server is back to operating with two redundant drives.

RAID is not a backup solution. RAID can get you, depending on the configuration, better throughput and/or better data reliability. If you lose a drive in some raid configurations, the system can continue working normally without that drive. Backups should copy data somewhere other than the machine hosting the original data. The page goes on:

So, after nearly six years, journalspace is no more.

After almost 6 years nobody had a cron job that backed up data to somewhere offsite (or a more complex backup system)? Ouch! My condolences to journalspace and its users on the loss.

Losing important data unexpectedly will sting you bad if you don't have appropriate backups. The only thing to do is learn from this mistake and move on, accepting the consequences of the loss.

This isn't the first website I've heard of having to shutdown because they permanently lost data. Learn from their mistakes, keep backups of your stuff!

Happy New Year to all TGS readers. I Wish You and Your Family a Happy and Healthy New Year 2009.

2008 was a fantastic year for my blog. I started this blog on May 2008 and currently it has 800+ subscribers and a Google Page Rank 4. I could have not achieved this without your tremendous support. I sincerely appreciate your support from my heart.

Visit the Best of the Blog section for the most popular article of 2008 on The Geek Stuff.

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Happy New Year 2009 - From Geek and The Doll