The <<- form of heredoc only ignores leading whitespace for the end delimiter. With Ruby 2.3 and later you can use a squiggly heredoc (<<~) to suppress the leading whitespace of content lines: def test <<~END First content line. Two spaces here. No space here. END end test # => “First content line.\n Two spaces … Read more
It’s a heredoc. http://en.wikipedia.org/wiki/Here_document#Ruby
This is known as heredoc syntax. The documentation will tell you everything you need to know. Essentially, however: A third way to delimit strings is the heredoc syntax: <<<. After this operator, an identifier is provided, then a newline. The string itself follows, and then the same identifier again to close the quotation. The closing … Read more
That’s heredoc syntax. You start a heredoc string by putting <<< plus a token of your choice, and terminate it by putting only the token (and nothing else!) on a new line. As a convenience, there is one exception: you are allowed to add a single semicolon after the end delimiter. Example: echo <<<HEREDOC This … Read more
You could do echo -e “import sys\nfor r in range(10): print ‘rob'” | python Or without pipes: python -c “exec(\”import sys\nfor r in range(10): print ‘rob’\”)” Or (echo “import sys” ; echo “for r in range(10): print ‘rob'”) | python Or SilentGhost’s answer or Crast’s answer.
In answer to your first question, there’s no parameter substitution because you’ve put the delimiter in quotes – the bash manual says: The format of here-documents is: <<[-]word here-document delimiter No parameter expansion, command substitution, arithmetic expansion, or pathname expansion is performed on word. If any characters in word are quoted, the delimiter is the … Read more
You can avoid a useless use of cat and handle mismatched quotes better with this: $ read -r -d ” VAR <<‘EOF’ abc’asdf” $(dont-execute-this) foo”bar”” EOF If you don’t quote the variable when you echo it, newlines are lost. Quoting it preserves them: $ echo “$VAR” abc’asdf” $(dont-execute-this) foo”bar”” If you want to use indentation … Read more
If you really want to do this but a bit simpler than using a class you can use: function fn($data) { return $data; } $fn = ‘fn’; $my_string = <<<EOT Number of seconds since the Unix Epoch: {$fn(time())} EOT;
Not as far as I know. The closest I know of is > out.txt ( @echo.bla @echo.bla … ) (@ prevents the command shell itself from printing the commands it’s running, and echo. allows you to start a line with a space.)
The heredoc syntax is much cleaner to me and it is really useful for multi-line strings and avoiding quoting issues. Back in the day I used to use them to construct SQL queries: $sql = <<<SQL select * from $tablename where id in [$order_ids_list] and product_name = “widgets” SQL; To me this has a lower … Read more