How do I start reading big file at specific line in ruby

Question

I have a really big file and somehow new data is appended to the end of the file. I only need to read the new data of this file. But now I have to read from the head of this file an scan the whole file.

Is there a good way to start read file from a specific line number? Or is there another way to solve it around?

Take a look at http://stackoverflow.com/questions/754494/reading-the-last-n-lines-of-a-file-in-ruby — Robert Kajic, Dec 27 '13 at 10:53

score 0 · Accepted Answer · answered Dec 27 '13 at 11:23

You can use the tail command from your shell, and use that inside ruby, like this:

lines = `tail -n 10 your_file.txt`

You can also install a gem named elif, which basically works like a regular File module, but allows you to read the file backwards :)

gem install elif

Now, you can do something like this to get the last line from your file:

Elif.open('your_file.txt', &:gets)

How do I start reading big file at specific line in ruby

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