How to print a line number in Ruby

Question

I\'m trying to go through a file to check every line with what white space it starts. we want to use space as a start or a tab. If one line starts with space and another line wi

Answer 1

Based on @zajn's answer:

file = File.open("filename.txt")
file.each do |line|
  puts "#{file.lineno}: #{line}"
end

Or you could use 'each with index':

File.open("another_file.txt").each_with_index do |line,i|
  puts "#{i}: #{line}"
end

which looks a touch less magical.

Answer 2

You should be able to use file.lineno to get the number of the current line you are reading in the file.

file = File.open("file_name")
file.each do |line|
  ...
  puts "#{file.lineno}: #{line}" # Outputs the line number and the content of the line
end