Replace single quote with backslash single quote
Solution 1:
The %q delimiters come in handy here:
# %q(a string) is equivalent to a single-quoted string
puts "Cote d'Ivoir".gsub("'", %q(\\\')) #=> Cote d\'Ivoir
Solution 2:
The problem is that \' in a gsub replacement means "part of the string after the match".
You're probably best to use either the block syntax:
a = "Cote d'Ivoir"
a.gsub(/'/) {|s| "\\'"}
# => "Cote d\\'Ivoir"
or the Hash syntax:
a.gsub(/'/, {"'" => "\\'"})
There's also the hacky workaround:
a.gsub(/'/, '\#').gsub(/#/, "'")