Pipeable Ruby - forget about grep / sed / awk / wc ... use pure, readable Ruby!

Map - each line

# count letters of each line
ls -1 | pru size

# select lines longer than five letters
ls -1 | pru 'size > 5'

# 2nd to last character
ls -1 | pru self[2..-1]

Reduce - all lines as Array

# count lines
ls -1 | pru -r size

# are the more than five lines?
ls -1 | pru -r 'size > 5'

# get 2nd to last line
ls -1 | pru -r self[2..-1]

Map and Reduce

# count letters in each line, then sum
ls -1 | pru size sum

# select lines longer than 5 letters, then join with commas
ls -1 | pru 'size > 5' 'join(",")'

Inplace edit

pru -i Gemfile 'sub /ruby/, "foo"'

Install

gem install pru

or standalone

curl https://rubinjam.herokuapp.com/pack/pru > pru && chmod +x pru
./pru -v

Options

-r, --reduce CODE                reduce via CODE

-I, --libdir DIR                 Add DIR to load path
    --require LIB                Require LIB (also comma-separated)
-i, --inplace-edit FILE          Edit FILE inplace

-h, --help                       Show this.
-v, --version                    Show Version

Examples

# grep --- all lines including foo
ls -al | grep foo
ls -al | pru /foo/

# grep --- all lines including current date
ls -al | grep $(date +"%Y-%m-%d")
ls -al | pru 'include?(Time.now.strftime("%Y-%m-%d"))'

# awk --- return second item
ls -al | awk '{print $2}'
ls -al | pru 'split(" ")[1]'

# awk --- count and average of all integers on second position
ls -al | awk '{ s += $2; } END {print "average" ,int(s/NR);print "count ",int(NR)}'
ls -al | pru 'split(" ")[1]' '"average #{mean(&:to_i)}\ncount #{size}"'

# wc --- count lines
ls -al | wc -l
ls -al | pru --reduce 'size'

# sed -- replace a 5 with five
ls -al | sed 's/5/five/'
ls -al | pru 'gsub(/5/,"five")'

# every second line
ls -al | pru 'i % 2 == 0'

# paste-friendly mime-types
curl https://raw.github.com/mattetti/mimetype-fu/master/lib/mime_types.yml | grep image | pru 'gsub(/(.*): (.*)/, %{"\\1" => "\\2",})'

# number of files by date:
ls -al | pru 'split(" ")[5]' 'grouped.sort_by{|d, f| -1 * f.size }.map{|d, f| "#{d} : #{f.size}" }'
ls -al | pru 'split(" ")[5]' 'counted'

# quotes inside a string
something | pru 'include?(%{"string"})'

# Find a gem version matching a requirement e.g. ~> 1.0.0
curl http://rubygems.org/api/v1/versions/bundler | pru --require json 'JSON.parse(self).map{|g|g["number"]}.find{|v| Gem::Requirement.new("~>1.0.1").satisfied_by? Gem::Version.new(v) }'

# List your local repos by watchers
ls | pru '[self, `curl --silent "https://github.com/grosser/#{self}"`.match(/<li class="watchers.*?(\d+)\s*<\/a/m)[1].to_i] rescue nil' 'sort_by(&:last).reverse.map{|n,i| "#{n} => #{i}" }'

# Cleanup strange whitespace in a file
pru -i Rakefile 'gsub(/\r\n/,"\n").gsub(/\t/,"  ")'

# Removing certain lines from output vs ruby -npe
ls -al | ruby -npe 'next unless $_.split(" ")[1].to_i > 3'
ls -al | pru 'split(" ")[1].to_i > 3'

Gemsets

Working with rvm / many gemsets -> only install once (or use standalone binary)

rvm 2.7.7 exec gem install pru
echo 'alias pru="rvm 2.7.2 exec pru"' >> ~/.bash_profile

Contributors

• John Hobbs
• Vasiliy Ermolovich
• Jens Wille
• SixArm

Michael Grosser
michael@grosser.it
License: MIT