"ruler" function for Bash/Zsh, print a ruler of given length to your terminal

ruler.sh

# Print out a line of text of given length to use as a rulter to resize your
# terminal. Requires some version of `ruby` to be installed on your system;
# I'm pretty sure it will work with versions as old as 1.8.3 up to the newest
# version 3.3.
#
# Install in your terminal by adding `source ruler.sh` (change filename as
# appropriate) to your .bashrc/.bash_profile or .zshrc/.zprofile file.
# Alternately, simply copy the function below in to one of those files.
#
# usage:
#   ruler [width, default 80] [units, default 10]
#
# example output:
#   $ ruler 40 10
#   0--------|---------|---------|--------40
#
# Updates can be found at:
#   https://gist.github.com/xunker/d0474365683e70680796d7cd67006259
ruler() {
  /usr/bin/env ruby -e "
    # ruler width as first agument, or 80 as default
    ruler_w = (ARGV[0] || 80).to_i

    # ruler "tick" mark spacing as second agument, or 10 as default
    ruler_tick_spacing = (ARGV[1] || 10).to_i

    # character to use for a ruler unit
    ruler_unit_char = '-'

    # character to use for a "tick" mark
    ruler_tick_char = '|'

    # generate the basic ruler string with tick marks
    ruler_str = ruler_w.times.map{|idx|
      ((idx+1) % ruler_tick_spacing) == 0 ? ruler_tick_char : ruler_unit_char
    }.join

    # Set beginning of ruler string to be "0"
    ruler_str[0] = '0'

    # Set ending of ruler string to be ruler length, offset from end
    ruler_str[((ruler_str.length-ruler_w.to_s.length))..-1] = ruler_w.to_s

    # print the ruler
    puts ruler_str
  " $*
}