On Sun, Dec 22, 2024 at 00:49:07 +0700, Budi wrote:
> How is Bash' code to store string of any characters should be containing
> pair of "" and '' at the same time explicitly, being exact verbatim
I'm interpreting this as:
* You would like to store some data in a string variable.
* The data is known at script-writing time (i.e. it's a "constant").
* The data contains both single and double quotes. (And let's say
backslashes too, just to avoid another round of questions.)
* You would like the least ugly solution possible.
So then, you have some choices to make.
For the purpose of this email, let's assume your data looks like this:
my "payload" has 'single quotes' \inside\ it
Choice #1: use '...' quoting, and change all internal single quotes.
In this form, every ' character must be replaced by the '\'' characters.
var='my "payload" has '\''single quotes'\'' \inside\ it'
Choice #2: use $'...' quoting, and change all internal single quotes
and backslashes. In this form, every ' is replaced by \' and every \
is replaced by \\ .
var=$'my "payload" has \'single quotes\' \\inside\\ it'
Choice #3: use "..." quoting, and change all internal double quotes,
dollar signs, backticks and backslashes. I won't bother showing this
one because it's a really poor choice.
Choice #4: use a here document. In this form, the line does not need
any modifications. However, there is a restriction: it must actually
be a single line of data, with no newlines inside it.
IFS= read -r var <<'EOF'
my "payload" has 'single quotes' \inside\ it
EOF
Choices 1 and 4 are POSIX sh compatible, in case you care about that.
Choice 2 is a bash extension. Choice 3 is also POSIX compatible, but
it's just bad.
If your data might have internal newlines, then you can extend choice 4
to read multiple lines:
var=$(cat <<'EOF'
my "payload" has 'single quotes' \inside\ it
and one newline
EOF
)
At this point, you're forking an external process to assign a constant
to a string variable, so you're pretty deep into "Why am I doing this,
exactly?" territory.
