Ruby `gsub` of escape character

Question

File escape.txt contains "/\\\\/" (slash, backslash, backslash, slash). File test_gsub.rb has:

content = File.open(ARGV[0]).read
content.gsub! content, content
puts content

This code will output "/\\\\/" (slash, backslash, slash), ie, oneback slash is escaped.

I am wondering if there is a way to disable this escape functionality. I want to output (slash, backslash, backslash, slash).

If I delete gsub , it will output (slash, backslash, backslash, slash).

This feature is important because I need to deal with raw text, and gsub will always escape these escape characters.

Answer 1

content.gsub! content, content => content

In the docs for gsub you can find this

If replacement is a String it will be substituted for the matched text. It may contain back-references to the pattern's capture groups of the form \\d, where d is a group number, or \\k, where n is a group name. If it is a double-quoted string, both back-references must be preceded by an additional backslash. However, within replacement the special match variables, such as $&, will not refer to the current match.

If the second argument is a Hash, and the matched text is one of its keys, the corresponding value is the replacement string.

Using a hash instead of a string prevents \\ from being treated specially.

Although the docs for gsub! don't mention the hash it seems to work fine (perhaps it's an oversight)