Issue
I have seen lots of uses of single and double-quotes in bash, as well as backtick-quotes, but have never seen what follows. What is the meaning of the transcript below, which seems to show that triple-single-quoting is recognized as meaningful by bash and further seems to show that single quotes inside this thing also have special meaning, enabling interpolation? I have found no documentation of this.
$ Q=test
$ echo '$Q' # <== I know, this doesn't work...
$Q # <== ...and so it doesn't.
$ echo '''$Q''' # <== Don't know what this could mean.
$Q # <== OK, nothing special?
$ echo ''' "$Q" ''' # <== Try a double-quote??
"$Q" # <== Hmm... OK, nothing.
$ echo ''' '$Q' ''' # <== Try a single-quote?
test # <== Wow, it did interpolate!?
$ echo '''
> ''' # <== Continuation! Proving bash
# thinks this is an opening
# quote of some kind.
$ bash --version # <== FYI, version info
GNU bash, version 3.2.57(1)-release (x86_64-apple-darwin18)
Copyright (C) 2007 Free Software Foundation, Inc.
Solution
There is no “triple quote” ... for example ''' '$Q' '''
is the concatenation of several strings ... ''
, ' '
, $Q
, ' '
and ''
. Consider each of the others in the same way.
Answered By - donkopotamus Answer Checked By - Mary Flores (WPSolving Volunteer)