A here document (also called a here-document, a heredoc, a hereis, a here-string or a here-script) is a way of specifying a string literal in command line shells including Unix shells (sh, csh, ksh, Bash and zsh) and in programming or scripting languages such as Perl, PHP, Python, PowerShell and Ruby. It preserves the line breaks and other whitespace (including indentation) in the text. Some languages allow variable substitution and command substitution inside the string.
The most common syntax for here documents is << followed by a delimiting identifier, followed, starting on the n...