The escape (\) preceding a character tells the shell to interpret that character literally.
A non-quoted backslash (\) is the escape character. It preserves the literal value of the next character that follows, with the exception of
. If a \
pair appears, and the backslash is not itself quoted, the \'' is treated as a line continuation (that is, it is removed from the input stream and effectively ignored).
Backslash-escaped characters with meaning, see Bash - CharacterArticles RelatedDocumentation / Reference