From: Alex Gutteridge <alexg@...>
Date: 2007-09-27T13:31:15+09:00
Subject: Re: some file operations

On 27 Sep 2007, at 12:23, blufur wrote:

> how can my ruby program tell me how many lines are in a text file?

IO.foreach iterates over the lines in a file which you can then  
count, or IO.read reads the whole thing into a string from which you  
can then count the number of lines.

> how can i have my ruby program edit the last line of a text file  
> (not add another line at the end, but get and then change the line  
> at the end).

Easiest (IMO) is to read the whole file, edit the last line and write  
back out. E.g:

lines = IO.read('file').split
lines[-1] = 'edit'
puts lines

> Thanks for any suggestions!

Alex Gutteridge

Bioinformatics Center
Kyoto University