Pass multiple arguments to single command in custom position xargs

Question

I want execute a command where I have the args as single string but they need to be in a custom position. E.g. in the following example I want the args to be positioned before any fixed args that I have written after the cp comamnd i.e. the path argument /somedir

I want:

echo -n 'file1 file2 file3' | xargs -d ' ' -I{} cp {} /somedir

to behave like:

cp file1 file2 file3 /somedir

but it doesn't...

It also looks like when including the -I{} option, the -d option makes xargs behave differently. It seems like it tries to pass each argument to a separate command call rather than all of them toa single one.

For example, this works:

echo -n 'file1 file2' | xargs -d' ' diff

But this fails

echo -n 'file1 file2' | xargs -d' ' -I{} diff {}

With error:

diff: missing operand after 'file1'
diff: Try 'diff --help' for more information.
diff: missing operand after 'file2'
diff: Try 'diff --help' for more information.

How can I get echo -n 'file1 file2 file3' | xargs -d ' ' -I{} cp {} /somedir to behave as intended

Answer 1

Like this:

$ echo -n 'file1 file2 file3' | xargs -d' ' bash -c 'echo cp "$@" /somedir' _arg0_
cp file1 file2 file3 /somedir

Not sure about your real use case but for the above example, the default xargs behavior would just work fine:

$ echo 'file1 file2 file3' | xargs bash -c 'echo cp "$@" /somedir' _arg0_
cp file1 file2 file3 /somedir

Answer 2

You can use an array for the args

read -a arg <<<"file1 file2 file3"
cp ${arg[@]} /some/dir

Answer 3

When you have the args as single string and separated with spaces, you don't need something special.
Examples:

single_string='file1 file2 file3'
cp ${single_string} /somedir

single_string='file1 file2'
diff ${single_string}

single_string='file_with_$_sign file[2]'
touch ${single_string}
ls -l ${single_string}
rm ${single_string}