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https://github.com/thisredone/rb

Turns Ruby into a versatile command line utility
https://github.com/thisredone/rb

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Turns Ruby into a versatile command line utility

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# rb



With 9 lines of Ruby replace most of the command line tools that you use to process text inside of the terminal.



Here's the code



```ruby

#!/usr/bin/env ruby

File.join(Dir.home, '.rbrc').tap { |f| load f if File.exist?(f) }



def execute(_, code)

  puts _.instance_eval(&code)

rescue Errno::EPIPE

  exit

end



single_line = ARGV.delete('-l')

code = eval("Proc.new { #{ARGV.join(' ')} }")

single_line ? STDIN.each { |l| execute(l.chomp, code) } : execute(STDIN.each_line, code)

```



Clone this repo and copy the `rb` file to somewhere in your path (or just copy and paste the above).



With this you can use ruby as a command line utility much more ergonomically than invoking it the standard way.



There's only one switch `-l` which runs your code on each line separately. Otherwise you get an Enumerator that returns the lines of stdin. It's `instance_eval`ed so some methods need `self` to work, eg. `self[-1]`



## Install



Just paste this line into your terminal to install `rb`:

```

sudo curl https://raw.githubusercontent.com/thisredone/rb/master/rb -o /usr/local/bin/rb && sudo chmod +x /usr/local/bin/rb

```



### Examples



###### Extract docker images from running containers



```bash

> docker ps | rb drop 1 | rb -l split[1]



# ubuntu

# postgres

```



###### Display how much time ago containers have exited



```shell

> docker ps -a | rb grep /Exited/ | rb -l 'split.last.ljust(20) + " => " + split(/ {2,}/)[-2]'



# angry_hamilton      => Exited (0) 18 hours ago

# dreamy_lamport      => Exited (0) 3 days ago

# prickly_hypatia     => Exited (0) 2 weeks ago

```



###### Sort `df -h` output by `Use%`



```shell

> df -h | rb 'drop(1).sort_by { |l| l.split[-2].to_f }'



# udev                         3,9G     0  3,9G   0% /dev

# tmpfs                        3,9G     0  3,9G   0% /sys/fs/cgroup

# /dev/sda1                    511M  3,4M  508M   1% /boot/efi

# /dev/sda2                    237M   85M  140M  38% /boot



# or leave the header if you want

> df -h | rb '[first].concat drop(1).sort_by { |l| l.split[-2].to_f }'



# Filesystem                   Size  Used Avail Use% Mounted on

# udev                         3,9G     0  3,9G   0% /dev

# tmpfs                        3,9G     0  3,9G   0% /sys/fs/cgroup

# /dev/sda1                    511M  3,4M  508M   1% /boot/efi

# /dev/sda2                    237M   85M  140M  38% /boot

```



###### Count files by their extension



```shell

> find . -type f | rb 'group_by(&File.method(:extname)).map { |ext, o| "#{ext.chomp}: #{o.size}" }'



# : 3

# .rb: 19

# .md: 1

```



###### This problem http://vegardstikbakke.com/unix/



```ruby

ls | rb 'group_by { |x| x[/\d+/] }.select { |_, y| y.one? }.keys'

```



## Extending rb



The `~/.rbrc` file is loaded if it's available. Anything defined in there will be available inside `rb` scripts.



```ruby

# ~/.rbrc



class String

  def black; "\033[30m#{self}\033[0m" end

  def red;   "\033[31m#{self}\033[0m" end

end

```



```shell

> ls | rb first.red

```



## Alternatives



For a more portable solution, note you can run `ruby` with the `-e` flag.



[`$<`](https://ruby-doc.org/3.2.1/globals_rdoc.html#:~:text=%24%3C,as%20ARGF.) is a two-character global equivalent to [`ARGF`](https://ruby-doc.org/3.2.1/ARGF.html). `ARGF` gives you access to the standard input and includes `Enumerable`.



```shell

> docker ps | ruby -e '$<.drop(1).each{puts _1.split[1]}'



# ubuntu

# postgres

```



```shell

> docker ps -a | ruby -e '$<.grep(/Exited/).each{puts _1.split.last.ljust(20) + " => " + _1.split(/ {2,}/)[-2]}'



# angry_hamilton      => Exited (0) 18 hours ago

# dreamy_lamport      => Exited (0) 3 days ago

# prickly_hypatia     => Exited (0) 2 weeks ago

```