Exercise 7

• https://dev.to/lofiandcode/ruby-puts-vs-print-vs-p-vs-pp-vs-awesome-5akl
• https://www.rubyguides.com/2018/10/puts-vs-print

Exercise 11

• https://rubyreferences.github.io/rubyref/appendix-a.html#io-and-strings

Exercise 13

ruby ex13.rb 12 17 29

• https://flatironschool.com/blog/a-short-explanation-of-argv
• the name of the called script

Exercise 16

ruby ex16.rb test.txt

• https://thoughtbot.com/blog/io-in-ruby#the-io-class
• https://thoughtbot.com/blog/io-in-ruby#file
• https://rubyapi.org/3.1/o/file#method-c-truncate
• https://rubyapi.org/3.1/o/io#method-i-seek
• https://stackoverflow.com/questions/27977368/seek-to-0-or-use-rewind-method

Exercise 17

echo "This is a test file." > test.txt

ruby ex17.rb test.txt new_file.txt

• https://rubyapi.org/3.1/o/file#method-c-exist-3F
• https://stackoverflow.com/questions/8590098/how-to-check-for-file-existence

Exercise 18

• https://www.justinweiss.com/articles/fun-with-keyword-arguments
• https://github.com/JuanitoFatas/what-do-you-call-this-in-ruby

Exercise 20

ruby ex20.rb test.txt

ri File#seek

• https://rubyapi.org/3.1/o/io#method-i-readline