puts / print / p / pp

puts value
puts value1, value2 # Multiple arguments are printed one per line.

# Outputs the value without a trailing newline.
print value

# Outputs a debug representation of the object (result of inspect).
p value
p value1, value2

# Outputs a more readable debug representation (Ruby 2.5+).
pp value

sample_puts_print_p_pp.rb

puts "Hello" # Hello
puts 42 # 42
puts [1, 2, 3] # One per line: 1, 2, 3

# print outputs without a newline.
print "A"
print "B"
print "C"
puts # Add a newline → ABC

# p prints the inspect result (useful for debugging).
p "Hello" # "Hello" (with quotes)
p nil # nil
p [1, "two", :three] # [1, "two", :three]

# Compare puts and p.
puts "hello" # hello (no quotes)
p "hello" # "hello" (with quotes)

# pp displays nested data in a readable format.
data = {
  name: "user_a",
  org: "org_a",
  techniques: ["skill_a", "skill_b", "skill_c"]
}
pp data

# printf prints output with a format string.
printf("Name: %-15s Org: %s\n", "user_a", "org_a")
printf("Name: %-15s Org: %s\n", "user_b", "org_a")

Running the code produces the following output:

ruby puts_print_p_pp.rb
Hello
42
1
2
3
ABC
"Hello"
nil
[1, "two", :three]
hello
"hello"
{name: "user_a",
 org: "org_a",
 techniques: ["skill_a", "skill_b", "skill_c"]}
Name: user_a   Org: org_a
Name: user_b  Org: org_a

Choose an output method based on your purpose. Use puts or print for user-facing output, and p or pp for debugging.

Because p returns the object itself, you can insert it in the middle of a method chain for quick debugging. Be careful not to leave p or pp calls in production code. These are debugging-only methods — use puts or a proper logger for production output.