"$@" expansion for user defined variables

Question

I'm trying to get a (bourne shell) variable to expand like "$@" so it produces multiple words with some having preserved spaces. I've tried defining the variable in many different ways but still can't get it to work:

#!/bin/sh

n=\"one\ two\"\ three
for i in "$n"; do
echo $i
done

I want to define the variable so the script outputs one two first and then three next iteration, which is what you'd get if you replaced the quoted variable with "$@" and passed 'one two' three as the arguments.

Is "$@" just magic?

score 4 · Accepted Answer · edited Aug 04 '15 at 01:55

4

So bourne shell (IIRC) doesn't support arrays. You can still use "$@"

set -- "one two" three
for i in "${@}" ; do
    echo "$i"
done

Outputs:

one two
three

Tested on AIX 7.1 bsh.

edited Aug 04 '15 at 01:55

cuonglm

153,898

answered Aug 03 '15 at 22:58

thanks, this does the trick. I guess this means "$@" is magic. – user126144 Aug 03 '15 at 23:09
2

@user126144 Yes, it is. "$@" is the only thing that expands to several words despite being in double quotes. (Shells that support arrays have the same thing with "${array_variable[@]}") – Gilles 'SO- stop being evil' Aug 03 '15 at 23:17
This answer discusses arrays in bash, ksh, zsh, and yash, – Scott - Слава Україні Jun 20 '17 at 01:35
Alternatively, printf '%s\n' "$@" – Kusalananda Jan 13 '19 at 14:10

"$@" expansion for user defined variables

1 Answers1