1

The following example returns "a b" instead of expected "a b c":

test() { bash -c "testargs() { echo \$@; }; testargs $@"; }
test "a b" c

It seems it's a quoting issue. How do I solve it without using "$*" instead?

2

$@ should pretty much only be used in the form "$@", alone in a word. When "stuff$@" is expanded, that results in a list consisting of the first positional parameter with stuff prepended, then the other positional parameters. For example, if the positional parameters are foo and bar, you get two words: stufffoo and bar. That's one of your problems.

Another problem is that with sh -c, the first non-option argument becomes the script name which is available as $0. Subsequent non-option arguments become positional parameters. So sh -c 'echo "$@"' foo bar qux prints bar qux — foo is in $0, bar in $1 and qux in$2.

To pass the arguments of the function to the script, use $@ in the script (not, like you did, in the function — "stuff$@" is expanded in the shell that executes the function, due to the double quotes). And account for $0.

test() { bash -c 'testargs() { echo "$@"; }; testargs "$@"' myscript "$@"; }
  • If the first argument is wasted as $0, then why did it return "a b" instead of "c"? – glarry Oct 4 '15 at 6:58
  • @glarry In your code, a b is the first positional parameter in the function call, and it gets to be part of the argument to the -c option in the call to bash. c is the second positional parameter in the function call, and it's $0 for the call to bash -c …. Your example is rather complex since it involves many successive expansions, I suggest to try simpler variations on it to get a feeling for how it works. – Gilles Oct 4 '15 at 13:10
1

$@ in double quotes expands to several words. bash -c accepts string as a parameter, but it can be followed by other words which are then assigned to positional parameters starting with $0.

You can therefore send the parameters to the code inside bash -c like this:

Test () { bash -c 'echo $@' -- "$@" ; }
Test "a b" c

This works for you case, too:

Test () { bash -c 'testargs() { echo $@ ; } ; testargs $@' -- "$@" ; }
Test "a b" c

If you want to keep the multiword parameters, add double quotes:

Test () {
    bash -c 'testargs() {
                 for a in "$@" ; do
                     echo "$a"
                 done
             }
             testargs "$@"' \
        -- "$@"
}
Test "a b" c

I used Test, as test already exists and might confuse readers.

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