# Rethinking the Generic Ruby Oneliner

**URL:** <https://www.ruby-forum.com/t/rethinking-the-generic-ruby-oneliner/90092>\
**Category:** Ruby\
**Created:** [March 26, 2007, 12:18am UTC](https://www.ruby-forum.com/t/rethinking-the-generic-ruby-oneliner/90092 "2007-03-26T00:18:23Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![amin1426](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/4da419/32.png) [@amin1426](https://www.ruby-forum.com/u/amin1426)\
**Post date:** [March 26, 2007, 12:18am UTC](https://www.ruby-forum.com/t/rethinking-the-generic-ruby-oneliner/90092/1 "2007-03-26T00:18:23Z")

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So I was asking myself the question… What ruby run time options  
would I add to make oneliners easier.

Basically awk started it all with the notion of a loop that iterated  
over a file allowing patterns and actions per line…

This is enshrined in ruby as…  
ruby -nple ‘do whatever with $_’  
or…  
ruby -nplae 'do whatever with $_ split into $F’

However, the ruby variants…  
IO.read( filename).gsub( %r{whatever}mx){|match| }  
and  
IO.read( filename).scan( %r{whatever}mx){|match| }  
are way more powerful.

The next Big Thing in one liners was the perl -i.bak option. Ruby has it  
too.

Invariably the -i.bak option is used in conjunction with the “find” and  
“xargs”  
commands to find the files.

Like so…  
find . -name ‘\*.[hc]’ | xargs ruby -i.bak -nple ‘whatever’

But Ruby has an excellent and way less cryptic find facility…

require ‘find’

Find.find( startPath) do |path|  
next unless path =~ %r{ .[hc] $ }x

# Do something with path

end

Wouldn’t it be nice if we could …

ruby --find startPath --matching pathRegex --scan scanRegex -e action  
or  
ruby --find startPath --matching pathRegex -i.bak --gsub searchRegex -e  
“replaceString”

with suitable one letter ‘-’ options replacing the --long options for  
golfing.

ruby --find startPath --matching pathRegex --prune ‘pruneRegex’ --scan  
scanRegex -e action

Would effectively expand to something vaguely like…  
require ‘find’  
Find.find( \*startPath.split(’,’)) do |path|  
next unless path.match( pathRegex)  
Find.prune if path.match( pruneRegex)  
IO.read(path).scan(scanRegex){|match| action}  
end

and…  
ruby --find startPath --matching pathRegex -i.bak --gsub searchRegex -e  
“replaceString”

Would effectively expand to something vaguely like…  
require ‘find’  
Find.find( \*startPath.split(’,’)) do |path|  
next unless path.match( pathRegex)  
Find.prune if path.match( pruneRegex)  
backup = path + ‘.bak’  
File.rename( path, backup)  
open( path, ‘w’) do |outf|  
outf.syswrite( IO.read( backup).gsub(searchRegex){|match|  
replaceString})  
end  
end

Any suggestions before I write up an RCR?

John C. Phone : (64)(3) 358 6639  
Tait Electronics Fax : (64)(3) 359 4632  
PO Box 1645 Christchurch Email : removed\_email\_address@domain.invalid  
New Zealand

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<div class="post-metadata">

**Author:** ![amin1426](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/4da419/32.png) [@amin1426](https://www.ruby-forum.com/u/amin1426)\
**Post date:** [March 26, 2007, 12:56am UTC](https://www.ruby-forum.com/t/rethinking-the-generic-ruby-oneliner/90092/2 "2007-03-26T00:56:28Z")

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Maybe:

> > ruby -rmylibrary -e “replaceString” – --find startPath --matching  
> > pathRegex -i.bak --gsub searchRegex

If that’s too long, maybe a shell/program wrapper ^^

> > myruby --find startPath --matching pathRegex -i.bak --gsub  
> > searchRegex -e “replaceString”

I like magic best when I can tear it apart – and you have all the  
tools now to put it to the test.

Paul

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<div class="post-metadata">

**Author:** ![amin1426](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/4da419/32.png) [@amin1426](https://www.ruby-forum.com/u/amin1426)\
**Post date:** [March 26, 2007, 8:01am UTC](https://www.ruby-forum.com/t/rethinking-the-generic-ruby-oneliner/90092/3 "2007-03-26T08:01:02Z")

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On Mon, Mar 26, 2007 at 07:55:05AM +0900, Paul S. wrote:

> Maybe:
> 
> > > ruby -rmylibrary -e “replaceString” – --find startPath --matching pathRegex -i.bak --gsub searchRegex
> 
> If that’s too long, maybe a shell/program wrapper ^^
> 
> > > myruby --find startPath --matching pathRegex -i.bak --gsub searchRegex -e “replaceString”

If you call it x.rb then you can have ruby -rx …

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<div class="post-metadata">

**Author:** ![amin1426](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/4da419/32.png) [@amin1426](https://www.ruby-forum.com/u/amin1426)\
**Post date:** [March 30, 2007, 9:06am UTC](https://www.ruby-forum.com/t/rethinking-the-generic-ruby-oneliner/90092/4 "2007-03-30T09:06:26Z")

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On 26.03.2007 08:00, Brian C. wrote:

> On Mon, Mar 26, 2007 at 07:55:05AM +0900, Paul S. wrote:
> 
> > Maybe:
> > 
> > > > ruby -rmylibrary -e “replaceString” – --find startPath --matching pathRegex -i.bak --gsub searchRegex  
> > > > If that’s too long, maybe a shell/program wrapper ^^
> > > 
> > > > myruby --find startPath --matching pathRegex -i.bak --gsub searchRegex -e “replaceString”
> 
> If you call it x.rb then you can have ruby -rx …

Or create a shell script (“rubyfind”) that does the command line  
parameter interpretation. You could even implement the shell script in  
ruby making your life much easier. 🙂

Kind regards

robert