file methods

read  a file:

input_file =File.new (filename, ‘r’)

write a file:

output_file= File.new( filename, ‘w’)

‘w+’: 

read and write.  When creating the file, the old file is overwritten 

'a':

append

read:

return the content of the file in the string

readlines:

output_file.readlines()

return an array with each line of the file

puts:

output_file.puts(“hello”)

write “hello” to output_file

close:

output_file.close()

close the file

show the files and directories under directory:

ex:

Dir.open("Desktop").entries

---> [ "." , "..", "test.c", "book"]

directory?

ex:

File.directory?("test")

extname:

ex:

File.extname("test.exe")

--> ".exe"