Rethinking the Generic Ruby Oneliner...

[John Carter]

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 Carter Phone : (64)(3) 358 6639
Tait Electronics Fax : (64)(3) 359 4632
PO Box 1645 Christchurch Email : (e-mail address removed)
New Zealand

 

[Paul Stickney]

MaybeathRegex -i.bak --gsub searchRegex

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

 

[Brian Candler]

Maybe:

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

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

 

[Robert Klemme]

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