Question

I read a text file to get some info from it and later on I need to rename the directory that the file sits in. I am not able do to that because the file is locked. If I comment out the function that reads from the file or if I manually unlock the file (unlocker utility) everything goes fine.

I am on ruby 1.8.7 (2010-08-16 patchlevel 302) [i386-mingw32]

This line leaves the file open File.open(file).readlines.each{|line|

These two lines leave the file open

    my_file=File.open(file,"r")
    my_file.collect {|line|

unless I close the file at the end using my_file.close

The man for core 1.8.7 of IO.html#method-c-open states

If the optional code block is given, it will be passed io as an argument, and the IO object will automatically be closed when the block terminates.

So I don’t understand why the file is still open.

What would be the one line code in 1.8.7 to read a text file and close it automatically?

Answer 1

The documentation is clear. However, you’re passing the block to collect. And since you’re not passing it to open, you are responsible for closing the file.

To have file auto-closed, try this:

File.open(file,"r") do |f|
  f.collect # or whatever
end