From: Bulhac Mihai [mailto:mihai.bulhac / yahoo.com] 
# how can i read only a line from a txt file?
# for example i want to read only line 3

you can open the file and then read each line, collecting the lines you want. exit anytime if you have what you want.

if you want a ready-made solution (written in ruby, of course), you can use rio.

irb(main):005:0> require 'rio'
=> true

# get first 4 lines (as always in ruby indexing starts at 0)

irb(main):006:0> rio('test.txt').lines[0..3] 
=> ["1testing \n", "2testing \n", "3asdfasdf\n", "\n"]

# get first lines 4 to 6

irb(main):007:0> rio('test.txt').lines[3..5]       # a range of lines
=> ["\n", "4asdf\n", "[]\n"]

# thus, reading line 3 would be

irb(main):013:0> rio('test.txt').lines[2..2]
=> ["3asdfasdf\n"]

kind regards -botp