From: Brian Candler <B.Candler@...>
Date: 2003-05-02T16:59:02+09:00
Subject: Re: Search string in a file

On Fri, May 02, 2003 at 11:51:11AM +0900, Daniel Carrera wrote:
> On Fri, May 02, 2003 at 10:04:09AM +0900, Panther wrote:
> > I must search string in a file ??
> > How I must open file in read and search string ??
> > What is syntax ??
> > Thamk you
> 
> Is this what you want?:
> 
> dcarrera ~ $ cat > file 
> cat
> dog 
> mouse
> eagle
> dcarrera ~ $ irb
> >> File.readlines("file").each { |line| puts line if line =~ /o/ }
> dog
> mouse
> >>

Perhaps better not to read the whole file in at once, but process it line at
a time:

  File.open("file").each_line { |line| puts line if line =~ /o/)

If you want to collect the results into an array, then simply

  res = File.open("file").grep(/o/)

or

  res = File.open("file") do |f|
    f.grep(/o/)
  end

The second form is a bit longer but has the advantage that the file will be
closed immediately after reading. The first form won't do this until
garbage-collection takes place.

Regards,

Brian.