running csv output through popen

gistfile1.txt

$ irb -r open3 -r csv
2.0.0-p247 :001 > Open3.popen2e("cat > blah") do |i,oe,t|
2.0.0-p247 :002 >     csv = CSV.new(i)
2.0.0-p247 :003?>   csv << [1,2,3,4]
2.0.0-p247 :004?>   csv.close
2.0.0-p247 :005?>   end
 => nil 
2.0.0-p247 :006 > quit

tamara@pontiki:~/Dropbox/Public/Examples:2013-07-10@12:00:08
$ file blah
blah: ASCII text

tamara@pontiki:~/Dropbox/Public/Examples:2013-07-10@12:00:12
$ more blah
1,2,3,4

gistfile2.txt

2.0.0-p247 :001 > Open3.popen2e("cat > blah") do |i,oe,t|
2.0.0-p247 :002 >     CSV(i) do |csv|
2.0.0-p247 :003 >       csv << [1,2,3,4,'five']
2.0.0-p247 :004?>     end
2.0.0-p247 :005?>   end
 => <#CSV io_type:IO encoding:UTF-8 lineno:1 col_sep:"," row_sep:"\n" quote_char:"\""> 
2.0.0-p247 :006 > quit

tamara@pontiki:~/Dropbox/Public/Examples:2013-07-10@12:15:12
$ file blah
blah: ASCII text

tamara@pontiki:~/Dropbox/Public/Examples:2013-07-10@12:15:17
$ cat blah
1,2,3,4,five