# My .irbrc for console/irb

**URL:** <https://www.ruby-forum.com/t/my-irbrc-for-console-irb/71935>\
**Category:** Ruby\
**Created:** [October 12, 2006, 2:32pm UTC](https://www.ruby-forum.com/t/my-irbrc-for-console-irb/71935 "2006-10-12T14:32:46Z")\
**Posts on this page:** 14\
**Page:** 1

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**Author:** ![nicwilliams](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/aca169/32.png) [@nicwilliams](https://www.ruby-forum.com/u/nicwilliams)\
**Post date:** [October 12, 2006, 2:32pm UTC](https://www.ruby-forum.com/t/my-irbrc-for-console-irb/71935/1 "2006-10-12T14:32:46Z")

</div>

I recently discovered that I can create a .irbrc file to run setup for  
my irb/console. I am in love.

My current .irbrc is:

require ‘irb/completion’  
require ‘map\_by\_method’  
require ‘what\_methods’  
require ‘pp’  
IRB.conf[:AUTO\_INDENT]=true

Explanation of the different libraries:  
[http://drnicwilliams.com/2006/10/12/my-irbrc-for-consoleirb/](http://drnicwilliams.com/2006/10/12/my-irbrc-for-consoleirb/)

Does anyone any interesting things in their .irbrc file?

Nic

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<div class="post-metadata">

**Author:** ![nicwilliams](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/aca169/32.png) [@nicwilliams](https://www.ruby-forum.com/u/nicwilliams)\
**Post date:** [October 12, 2006, 2:59pm UTC](https://www.ruby-forum.com/t/my-irbrc-for-console-irb/71935/2 "2006-10-12T14:59:51Z")

</div>

On 12/10/06, Dr Nic [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> 

I haven’t used it but Wirble([http://pablotron.org/software/wirble/](http://pablotron.org/software/wirble/))  
looks pretty cool.

Farrel

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<div class="post-metadata">

**Author:** ![nicwilliams](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/aca169/32.png) [@nicwilliams](https://www.ruby-forum.com/u/nicwilliams)\
**Post date:** [October 12, 2006, 3:19pm UTC](https://www.ruby-forum.com/t/my-irbrc-for-console-irb/71935/3 "2006-10-12T15:19:20Z")

</div>

Farrel L. wrote:

> On 12/10/06, Dr Nic [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:
> 
> > 
> 
> I haven’t used it but Wirble([http://pablotron.org/software/wirble/](http://pablotron.org/software/wirble/))  
> looks pretty cool.

Very nifty indeed.

---

<div class="post-metadata">

**Author:** ![nicwilliams](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/aca169/32.png) [@nicwilliams](https://www.ruby-forum.com/u/nicwilliams)\
**Post date:** [October 13, 2006, 9:48pm UTC](https://www.ruby-forum.com/t/my-irbrc-for-console-irb/71935/4 "2006-10-13T21:48:56Z")

</div>

On 10/12/06, Dr Nic [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Does anyone any interesting things in their .irbrc file?

I don’t know why I hadn’t thought of it before but I just added:

# show\_regexp - stolen from the pickaxe

def show\_regexp(a, re)  
if a =~ re  
“#{$`}\<\<#{$&}\>\>#{$'}”  
else  
“no match”  
end  
end

# Convenience method on Regexp so you can do

# /an/.show\_match(“banana”)

class Regexp  
def show\_match(a)  
show\_regexp(a, self)  
end  
end

–  
Rick DeNatale

My blog on Ruby  
[http://talklikeaduck.denhaven2.com/](http://talklikeaduck.denhaven2.com/)

IPMS/USA Region 12 Coordinator  
[http://ipmsr12.denhaven2.com/](http://ipmsr12.denhaven2.com/)

Visit the Project Mercury Wiki Site  
[http://www.mercuryspacecraft.com/](http://www.mercuryspacecraft.com/)

---

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**Author:** ![nicwilliams](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/aca169/32.png) [@nicwilliams](https://www.ruby-forum.com/u/nicwilliams)\
**Post date:** [October 18, 2006, 10:38am UTC](https://www.ruby-forum.com/t/my-irbrc-for-console-irb/71935/5 "2006-10-18T10:38:41Z")

</div>

Nice, thanks!

You may find it useful to extend your #what? with #what\_returns?(x)

[1, 2, 3].what\_returns?(1) #=\> [:first]

Used in some method browsers in Squeak. Could be extended in all kinds  
of  
ways - state change, parameters,…

---

<div class="post-metadata">

**Author:** ![nicwilliams](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/aca169/32.png) [@nicwilliams](https://www.ruby-forum.com/u/nicwilliams)\
**Post date:** [October 12, 2006, 4:36pm UTC](https://www.ruby-forum.com/t/my-irbrc-for-console-irb/71935/6 "2006-10-12T16:36:26Z")

</div>

On 10/12/06, Dr Nic [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> I recently discovered that I can create a .irbrc file to run setup for  
> my irb/console. I am in love.
> 
> Does anyone any interesting things in their .irbrc file?

Sure, see

> **[Content for Whom? — err.the\_blog](http://errtheblog.com/post/26)**
>
> Err the Blog: Ruby and Rails from the front.

[http://blog.nicksieger.com/articles/2006/04/23/tweaking-irb](http://blog.nicksieger.com/articles/2006/04/23/tweaking-irb)

Cheers,  
/Nick

---

<div class="post-metadata">

**Author:** ![nicwilliams](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/aca169/32.png) [@nicwilliams](https://www.ruby-forum.com/u/nicwilliams)\
**Post date:** [October 18, 2006, 10:38am UTC](https://www.ruby-forum.com/t/my-irbrc-for-console-irb/71935/7 "2006-10-18T10:38:53Z")

</div>

On Thu, 2006-10-12 at 21:32 +0900, Dr Nic wrote:

> I recently discovered that I can create a .irbrc file to run setup for  
> my irb/console. I am in love.
> 
> …
> 
> Does anyone any interesting things in their .irbrc file?

### I have these to help keep output manageable:

class Array  
alias :\_\_orig\_inspect :inspect

def inspect  
(length \> 20) ? “[… #{length} elements …]” : \_\_orig\_inspect  
end  
end

class Hash  
alias :\_\_orig\_inspect :inspect

def inspect  
(length \> 20) ? “{ … #{length} keys … }” : \_\_orig\_inspect  
end  
end

#### This for history (I believe I got it from Rubygarden):

HISTFILE = “~/.irb.hist”  
MAXHISTSIZE = 100

begin  
if defined? Readline::HISTORY  
histfile = File::expand\_path( HISTFILE )  
if File::exists?( histfile )  
lines = IO::readlines( histfile ).collect {|line| line.chomp}  
puts “Read %d saved history commands from %s.” %  
[lines.nitems, histfile] if $DEBUG || $VERBOSE  
Readline::HISTORY.push( \*lines )  
else  
puts “History file ‘%s’ was empty or non-existant.” %  
histfile if $DEBUG || $VERBOSE  
end

```
Kernel::at_exit {
  lines = Readline::HISTORY.to_a.reverse.uniq.reverse
  lines = lines[-MAXHISTSIZE, MAXHISTSIZE] if lines.nitems >

```

MAXHISTSIZE  
$stderr.puts “Saving %d history lines to %s.” %

```
    [lines.length, histfile] if $VERBOSE || $DEBUG
  File::open( histfile, File::WRONLY|File::CREAT|File::TRUNC ) {|

```

ofh|  
lines.each {|line| ofh.puts line }  
}  
}  
end  
end

#### And this for RI (again, from Rubygarden or someone’s blog, I forget

which):

def ri arg  
puts `ri #{arg}`  
end

class Module  
def ri(meth=nil)  
if meth  
if instance\_methods(false).include? meth.to\_s  
puts `ri #{self}##{meth}`  
else  
super  
end  
else  
puts `ri #{self}`  
end  
end  
end

---

<div class="post-metadata">

**Author:** ![nicwilliams](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/aca169/32.png) [@nicwilliams](https://www.ruby-forum.com/u/nicwilliams)\
**Post date:** [October 18, 2006, 10:38am UTC](https://www.ruby-forum.com/t/my-irbrc-for-console-irb/71935/8 "2006-10-18T10:38:44Z")

</div>

On 10/12/06, Dr Nic [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Explanation of the different libraries:  
> [http://drnicwilliams.com/2006/10/12/my-irbrc-for-consoleirb/](http://drnicwilliams.com/2006/10/12/my-irbrc-for-consoleirb/)
> 
> Does anyone any interesting things in their .irbrc file?

Mine is rather large and in flux right now but I will post a few  
nuggets from it bellow:

require ‘rubygems’

# Very basic prelude of enhancements for Object

module ObjectEnhancer

def clone!  
self.clone rescue self  
end

def tap  
yield self  
self  
end

def \_  
yield if block\_given?  
nil  
end

end

class Object  
include ObjectEnhancer  
end

# Lazy loading prety print support

class Object  
def pp(\*a, &b) # pass the block just-in-case this changes.  
require ‘pp’  
pp(\*a, &b)  
end  
end

# Tab completion

require ‘irb/completion’  
IRB.conf[:USE\_READLINE] = true

# Histories

require ‘irb/ext/save-history’  
IRB.conf[:SAVE\_HISTORY] = 1000  
IRB.conf[:EVAL\_HISTORY] = 100

# Prompts

IRB.conf[:PROMPT][:CUSTOM] = {  
:PROMPT\_N =\> "\>\> ",  
:PROMPT\_I =\> "\>\> ",  
:PROMPT\_S =\> nil,  
:PROMPT\_C =\> " \> ",  
:RETURN =\> “=\> %s\n”  
}

# Set default prompt

IRB.conf[:PROMPT\_MODE] = :CUSTOM

# Simple ri integration

def ri(\*names)  
system(“ri #{names.map {|name| name.to\_s}.join(” “)}”)  
end

# fresh irb. It uses an at\_exit handler to yield it a block is given.

def reset\_irb  
at\_exit {exec($0)} # first registered is last to run  
at\_exit {yield if block\_given?}

# From finalizer code in irb/ext/save-history.rb… very ugly way to

do it :S… who wants to rewrite irb?  
if num = IRB.conf[:SAVE\_HISTORY] and (num = num.to\_i) \> 0  
if hf = IRB.conf[:HISTORY\_FILE]  
file = File.expand\_path(hf)  
end  
file = IRB.rc\_file(“\_history”) unless file  
open(file, ‘w’) do |file|  
hist = IRB::HistorySavingAbility::HISTORY.to\_a  
file.puts(hist[-num…-1] || hist)  
end  
end

# Make irb give us a clean exit (up until our at\_exit handler above)

throw :IRB\_EXIT, 0  
end

# clear the screen… with some self destruction 😉

def clear  
eval “def clear; print #{`clear`.inspect} end”  
clear  
end  
private :clear

# Simple webserver (Loazy loading)

def serve\_files(opts = {})  
require ‘webrick’

opts[:host] ||= Socket.gethostname  
opts[:dir] ||= Dir.pwd  
opts[:port] ||= opts[:dir].hash % 1000 + 10000  
opts[:log] ||= Nop.new # hidden and simple.

server = WEBrick::HTTPServer.new(  
:Host =\> opts[:host],  
:Port =\> opts[:port],  
:DocumentRoot =\> opts[:dir],  
:Logger =\> opts[:log]  
)

trap(“INT”) {server.shutdown}

puts “Serving "#{opts[:dir]}" at  
http://#{opts[:host]}:#{opts[:port]}/”  
server.start  
nil  
rescue  
puts “Failed to start server! See $webrick\_error for the exception.”  
$webrick\_error = $!  
nil  
end  
private :serve\_files

# SSH support. Needs a lot of work still but it is nice to have.

# This was just a 5 min hack. Thanks goes to Jamis for the

# nice library.

# Note that you must sleep to have the event loop run.

def ssh\_session(opts = {})  
puts “Note: You must ‘sleep’ in order for the event loop to run in  
irb.” if require ‘net/ssh’

dynamic\_session\_class = Class.new do  
@@default\_opts = {  
:user =\> ENV[‘USER’] || ENV[‘USERNAME’],  
:port =\> 22  
}.freeze

```
def initialize(opts = {}, aux = {})
  opts, opts[:host] = aux, opts unless Hash === opts
  opts = aux.merge opts
  opts = @@default_opts.merge opts

  @shutdown = false
  @queue = []

  ready = false
  Thread.new {
    begin
      Net::SSH.start(opts[:host],
        :username => opts[:user],
        :password => opts[:password],
        :port => opts[:port]
      ) do |session|
        ready = true
        loop {
          break if self.shutdown?
          self.process(session)
          session.loop
          sleep 0.01
        }
      end
    rescue
      puts "Failed while running ssh session! See $ssh_error for

```

the exception."  
$ssh\_error = $!  
ensure  
ready = true  
end  
}  
sleep 0 until ready  
end

```
def shutdown?
  @shutdown
end

def shutdown
  @shutdown = true
end

def execute(&blk)
  raise "Session shutdown" if shutdown?
  @queue << blk
  nil
end

def process(session)
  while proc = @queue.pop
    proc.call(session)
  end
end

def forward_local(port, host, aux_port = port)
  execute {|session|
    session.forward.local('0.0.0.0', port, host, aux_port)
  }
end
alias outgoing forward_local

def forward_remote(port, host, aux_port = port)
  execute {|session|
    session.forward.remote_to(port, host, aux_port)
  }
end

def shell
  require 'termios'
  puts "Note: You will need to interrupt 'sleep' when your shell

```

is done (usually ^C)."  
execute {|session|  
stdin\_buffer = lambda do |enable|  
attrs = Termios::getattr($stdin)  
if enable  
attrs.c\_lflag |= Termios::ICANON | Termios::ECHO  
else  
attrs.c\_lflag &= ~(Termios::ICANON | Termios::ECHO)  
end  
Termios::setattr($stdin, Termios::TCSANOW, attrs)  
end

```
    begin
      stdin_buffer[false]

      shell = session.shell.open(:pty => true)

      loop do
        break unless shell.open?
        if IO.select([$stdin],nil,nil,0.01)
          data = $stdin.sysread(1)
          shell.send_data data
        end

        $stdout.print shell.stdout while shell.stdout?
        $stdout.flush
      end
    ensure
      stdin_buffer[true]
    end
  }
  sleep
end
alias incoming forward_remote

```

end

Object.const\_set(‘DynamicSSHSession’, dynamic\_session\_class) unless  
Object.constants.include? ‘DynamicSSHSession’

dynamic\_session\_class.new(opts)  
rescue  
puts “Failed to create an ssh session! See $ssh\_error for the  
exception.”  
$ssh\_error = $!  
end  
private :ssh\_session

# Like haskell’s sequence. Really nice to have but recursive.

# I should change this it an iterative solution sometime.

# Recursion is usually not a problem for realistic inputs.

class Array  
def sequence(i = 0, \*a)  
return [a] if i == size  
self[i].map {|x|  
sequence(i+1, \*(a + [x]))  
}.inject([]) {|m, x| m + x}  
end  
end

class Symbol  
def to\_proc  
lambda {|\*args| args.shift. **send** (self, \*args)}  
end  
end

# Modulized blank slate. Only removes current not future

# methods for simplicities sake.

module Blank  
def self.append\_features(base)  
base.module\_eval {  
instance\_methods.each {|m| undef\_method m unless m =~ /^\_\_/}  
}  
end  
end

# This is mostly a toy but it has been useful in a few cases

# where I needed to slowly build up a proc inside multiple

# calls

class It \< Proc  
instance\_methods.each {|m| undef\_method m unless m =~ /^\_\_/}

def method\_missing(\*args, &blk)  
It.new {|x|  
Proc.instance\_method(:call).bind(self).call(x).send(\*args, &blk)}  
end  
end

def it  
if block\_given?  
It.new  
else  
It.new {|x| x}  
end  
end  
private :it

That is about half of it. I’ve got more stuff like gray number stuf,  
unbound method extensions, and some new meta-programming stuff but it  
all needs a little more work first. I should also note that I wrap my  
irbrc file with a begin rescue end. The rescue just prints the  
presence of an error and then shoves $! into $irbrc\_error. This is  
nice for occasions when you might be trying out new 1.9 builds or use  
rails (they don’t correctly initialize IRB so it causes failed loads  
of irbrc – keeps the output a little cleaner).

I will probably do another clean-up before RubyConf so we can all  
share .irbrc’s ;-). I’ll probably end up removing more things then I  
add (i.e. I really don’t use Symbol#to\_proc that much).

One last thing, I was wondering if anyone would be interested in a  
series of gems that act as automatic irb plugins? it might be fun to  
gemify some of these things.

Brian.

---

<div class="post-metadata">

**Author:** ![nicwilliams](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/aca169/32.png) [@nicwilliams](https://www.ruby-forum.com/u/nicwilliams)\
**Post date:** [October 18, 2006, 10:39am UTC](https://www.ruby-forum.com/t/my-irbrc-for-console-irb/71935/9 "2006-10-18T10:39:51Z")

</div>

Ross B. wrote:

> ```
> if instance_methods(false).include? meth.to_s
> puts `ri #{self}##{meth}`
> else
> super
> end
> else
> puts `ri #{self}`
> end
> 
> ```
> 
> end  
> end

I _think_ that came out of my .irbrc, but it’s always missed one thing:  
a nice notation for class methods:

## irb(main):014:0\> IO.ri “close” --------------------------------------------------------------- IO#close ios.close =\> nil

…

irb(main):015:0\> IO.ri “open”  
More than one method matched your request. You can refine  
your search by asking for information on one of:  
…

Of course you can always do this:

irb(main):016:0\> ri “IO.open”  
--------------------------------------------------------------- IO::open  
IO.open(fd, mode\_string=“r” ) =\> io  
IO.open(fd, mode\_string=“r” ) {|io| block } =\> obj

---

<div class="post-metadata">

**Author:** ![nicwilliams](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/aca169/32.png) [@nicwilliams](https://www.ruby-forum.com/u/nicwilliams)\
**Post date:** [October 18, 2006, 10:44am UTC](https://www.ruby-forum.com/t/my-irbrc-for-console-irb/71935/10 "2006-10-18T10:44:08Z")

</div>

[@everyone](https://www.ruby-forum.com/groups/everyone) - that is a great dump ideas. Very cool. (sorry for not  
replying earlier - Ruby Forum’s email notifier seemed to have been  
playing up).

Re: RubyConf - It’d be great to see an irb\_tools gem come out of the  
conference now! 🙂

Nic

---

<div class="post-metadata">

**Author:** ![nicwilliams](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/aca169/32.png) [@nicwilliams](https://www.ruby-forum.com/u/nicwilliams)\
**Post date:** [October 18, 2006, 1:01pm UTC](https://www.ruby-forum.com/t/my-irbrc-for-console-irb/71935/11 "2006-10-18T13:01:07Z")

</div>

On 10/18/06, Dr Nic [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> [@everyone](https://www.ruby-forum.com/groups/everyone) - that is a great dump ideas. Very cool. (sorry for not  
> replying earlier - Ruby Forum’s email notifier seemed to have been  
> playing up).
> 
> Re: RubyConf - It’d be great to see an irb\_tools gem come out of the  
> conference now! 🙂

It’s sad you mention that. Ironic too [1]. I had to cancel my trip  
yesterday on request from the company I work for. I’ll definitely miss  
going but I’ll avoid thinking about it to avoid souring the rest my  
week too badly. So… please take great notes!

I still want to sit down and clean up my irb stuff into plugins. Maybe  
I’ll setup a Rubyforge project after crunch time has died down at  
work. BUT don’t let that stop anyone from beating me to the punch.

Brian.

[1] I have been sad to see many friends cancel their trips as well  
telling them I would miss their attendance.

---

<div class="post-metadata">

**Author:** ![nicwilliams](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/aca169/32.png) [@nicwilliams](https://www.ruby-forum.com/u/nicwilliams)\
**Post date:** [October 18, 2006, 10:39am UTC](https://www.ruby-forum.com/t/my-irbrc-for-console-irb/71935/12 "2006-10-18T10:39:54Z")

</div>

Dr Nic wrote:

> Does anyone any interesting things in their .irbrc file?

This is useful sometimes:

def dump\_history(file=nil)  
if file  
File.open(file, “w”) do |f|  
f.puts IRB::ReadlineInputMethod::HISTORY.to\_a  
end  
else  
puts IRB::ReadlineInputMethod::HISTORY.to\_a  
end  
end

And there is this gem from Logan C.:

def reset\_irb  
exec($0)  
end

---

<div class="post-metadata">

**Author:** ![nicwilliams](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/aca169/32.png) [@nicwilliams](https://www.ruby-forum.com/u/nicwilliams)\
**Post date:** [October 18, 2006, 4:32pm UTC](https://www.ruby-forum.com/t/my-irbrc-for-console-irb/71935/13 "2006-10-18T16:32:45Z")

</div>

I’ve been using this guy for code that prints copious output to the  
terminal. I’m sure it could be improved a bit, but I’ve found it  
useful.

def less  
require ‘stringio’  
$stdout, sout = StringIO.new, $stdout  
yield  
$stdout, str\_io = sout, $stdout  
IO.popen(‘less’, ‘w’) do |f|  
f.write str\_io.string  
f.flush  
f.close\_write  
end  
end

I tend to use that in conjunction with yaml dumps to look at complex  
data structures, rather than pp, but that would work just as well.

def yp(\*data)  
require ‘yaml’  
puts YAML::dump(\*data)  
end

Give them a whirl like so:

$ irb  
less { yp IRB.conf }

---

<div class="post-metadata">

**Author:** ![nicwilliams](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/aca169/32.png) [@nicwilliams](https://www.ruby-forum.com/u/nicwilliams)\
**Post date:** [October 18, 2006, 1:05pm UTC](https://www.ruby-forum.com/t/my-irbrc-for-console-irb/71935/14 "2006-10-18T13:05:16Z")

</div>

Brian M. wrote:

> On 10/18/06, Dr Nic [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:
> 
> > [@everyone](https://www.ruby-forum.com/groups/everyone) - that is a great dump ideas. Very cool. (sorry for not  
> > replying earlier - Ruby Forum’s email notifier seemed to have been  
> > playing up).
> > 
> > Re: RubyConf - It’d be great to see an irb\_tools gem come out of the  
> > conference now! 🙂
> 
> It’s sad you mention that. Ironic too [1]. I had to cancel my trip  
> yesterday on request from the company I work for. I’ll definitely miss  
> going but I’ll avoid thinking about it to avoid souring the rest my  
> week too badly. So… please take great notes!

I misconstrude my attendence - I’m not able to go. Went to Railsconf,  
wife said “that will be sufficient for you for the year” (we’re in  
Europe). Bummer. But she’s excited about Railsconf2007 - she wants to go  
on holidays in California 🙂

> I still want to sit down and clean up my irb stuff into plugins. Maybe  
> I’ll setup a Rubyforge project after crunch time has died down at  
> work. BUT don’t let that stop anyone from beating me to the punch.

Remember to use newgem scaffolding for all your new gem generation needs  
🙂

[http://drnicwilliams.com/2006/10/11/generating-new-gems/](http://drnicwilliams.com/2006/10/11/generating-new-gems/)

Nic