Ruby - Delete the last character in a file?

Question

Seems like it must be easy, but I just can't figure it out. How do you delete the very last character of a file using Ruby IO?

I took a look at the answer for deleting the last line of a file with Ruby but didn't fully understand it, and there must be a simpler way.

Any help?

Answer 1

There is File.truncate:

truncate(file_name, integer) → 0

Truncates the file file_name to be at most integer bytes long. Not available on all platforms.

So you can say things like:

File.truncate(file_name, File.size(file_name) - 1)

That should truncate the file with a single system call to adjust the file's size in the file system without copying anything.

Note that not available on all platforms caveat though. File.truncate should be available on anything unixy (such as Linux or OSX), I can't say anything useful about Windows support.