#Put some stuff into a file.
open('sample_file', 'w') do |f| 
  f.write("This is line one.\nThis is line two.") 
end

Then read it back out.

open('sample_file') { |f| f.read }

File.read('sample_file')

open('sample_file') { |f| f.readlines }

open('sample_file').each { |x| p x }

"This is line one.\n"
"This is line two."

"This is line one.\n"
"This is line two."

puts open('conclusion') { |f| f.read(50) }

"I know who killed Mr. Lambert," said Joe. "It was
Create a file...

Error! (Exception?) Here's stdout:
Errno::ENOENT: No such file or directory - conclusion
	from (irb):9:in `initialize'
	from (irb):9

open('end_separated_records', 'w') do |f|
  f << %{This is record one.
It spans multiple lines.ENDThis is record two.END}
end

And read it back in.

open('end_separated_records') { |f| f.each('END') { |record| p record } }

"This is record one.\nIt spans multiple lines.END"
"This is record two.END"
Create a file...

"This is record one.\nIt spans multiple lines.END"
"This is record two.END"

open('pipe_separated_records', 'w') do |f|
  f << "This is record one.|This is record two.|This is record three."
end

And read it back in.

open('pipe_separated_records') { |f| f.readlines('|') }

open('newline_separated_records', 'w') do |f|
  f.puts 'This is record one. It cannot span multiple lines.'
  f.puts 'This is record two.'
end
open('newline_separated_records') { |f| f.each { |x| p x } }

"This is record one. It cannot span multiple lines.\n"
"This is record two.\n"

"This is record one. It cannot span multiple lines.\n"
"This is record two.\n"

open('file_from_unknown_os') { |f| f.read().split(/\r?\n|\r(?!\n)/) }
"This line has a Unix/Mac OS X newline.\n".chomp

"This line has a Windows newline.\r\n".chomp

"This line has an old-style Macintosh newline.\r".chomp

"This string contains two newlines.\n\n".chomp

"This string contains two newlines.\n"

'This is record two.END'.chomp('END')

'This string contains no newline.'.chomp

open('pipe_separated_records') do |f| 
  f.each('|') { |l| puts l.chomp('|') }
end

This is record one.
This is record two.
This is record three.

This is record one.
This is record two.
This is record three.

lines = open('pipe_separated_records') { |f| f.readlines('|') }

lines.each { |l| l.chomp!('|') }

class File
  def each_chunk(chunk_size=1024)
    yield read(chunk_size) until eof?
  end
end
open("pipe_separated_records") do |f|
  f.each_chunk(15) { |chunk| puts chunk }
end

This is record
one.|This is re
cord two.|This
is record three
.

This is record 
one.|This is re
cord two.|This 
is record three
.