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do sth. on eachline from STDIN

/ Published in: Ruby
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This script is intended to use after the pipe '|' on unix shell. It execute a one-line ruby code(you can split multi-line ruby-code with ';', of course) iteratively on each-line from the STDIN, each-line of which is assigned to a variable x.

eg.
ls | eachline.rb '$no||=1;puts "#$no - #{x}";$no+=1'
the output looks like this:
1 - README.image
2 - README.image~
3 - bin
4 - boot
...

Simple enough, isn't it?

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  1. #!/usr/bin/env ruby
  2. #supress any warning when calling other shell commands.
  3. $VERBOSE = nil
  4.  
  5. def die(msg)
  6.         puts msg
  7.         exit 1
  8. end
  9.  
  10. $cmd = ARGV.shift
  11. die "you should specify a string of ruby code to deal with eachline of STDIN" unless $cmd
  12.  
  13. $in = STDIN.readlines
  14. $in.each do |x|
  15.         x.chomp!
  16.         eval($cmd)
  17. end

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