String#chomp

str.chomp(separator)

Returns: String · Updated March 14, 2026 · String Methods

ruby string newline stripping

The chomp method removes the trailing record separator from a string. By default, it removes \n, \r\n, or \r depending on the platform. This is particularly useful when reading lines from files or user input, where you typically want to remove the trailing newline.

Basic Usage

When called without arguments, chomp removes any trailing newline characters:

"hello\n".chomp
# => "hello"

"hello\r\n".chomp
# => "hello"

"hello\r".chomp
# => "hello"

If there’s no trailing separator, chomp returns the string unchanged:

"hello".chomp
# => "hello"

Specifying a Custom Separator

You can pass a string argument to remove a custom trailing separator:

"hello!".chomp("!")
# => "hello"

"path/to/file/".chomp("/")
# => "path/to/file"

"data---".chomp("---")
# => "data"

Using a Regex Separator

A regular expression can be used to remove more complex trailing patterns:

"hello123".chomp(/\d+/)
# => "hello"

"foo.bar.baz".chomp(/\.[a-z]+/)
# => "foo.bar"

Multiple Separators

If the separator appears multiple times at the end, chomp only removes one occurrence:

"hello\n\n".chomp
# => "hello\n"

"test!!!".chomp("!!")
# => "test!"

Practical Example: Processing File Lines

When reading lines from a file, chomp is essential to remove the trailing newline:

File.readlines("data.txt").each do |line|
  cleaned = line.chomp
  puts cleaned.upcase
end

Comparison with Strip

While chomp only removes trailing record separators, strip removes both leading and trailing whitespace:

"  hello  \n".chomp
# => "  hello  "

"  hello  \n".strip
# => "hello"

"\tdata\t".chomp
# => "\tdata\t"

"\tdata\t".strip
# => "data"

Comparison with Chop

The chop method removes the last character unconditionally, while chomp only removes record separators:

"hello\n".chop
# => "hell"

"hello\n".chomp
# => "hello"

"hello!".chop
# => "hell"

"hello!".chomp("!")
# => "hello"

Common Pitfall: Mutating the Original String

Remember that chomp returns a new string and does not modify the original. Use chomp! if you need in-place modification:

str = "hello\n"
str.chomp
puts str.inspect    # => "hello\n"

str.chomp!
puts str.inspect    # => "hello"