Re: for loop with variable

Standard brace expansion uses commas to separate individual options and
double-dots to separate ranges. Using commas instead of spaces doesn't save
any typing for single lists, but since you can put multiple such expansions
together, which turns into _every possible combination_, it can save a lot
of typing indeed:

% print -l {a,b,c}{1,2,3}

a1
a2
a3
b1
b2
b3
c1
c2
c3


Instant "outer product", as the nerds say.

It also works in bash and ksh. Although the timing is wonky in bash; brace
expansion happens _before_ parameters, so this doesn't work:

$ x=3; echo {1..$x}
*ksh, zsh*: 1 2 3
*bash*: {1..3}


Also, FWIW, if you're going to put your options into a variable, I
recommend an array:

var=({a..c})
for aa in $var; do # no = needed


On Mon, May 11, 2026 at 12:45 PM Ray Andrews <[email protected]> wrote:

> % var=" a b c "
>
> % for aa in $=var; do echo $aa; done
> a
> b
> c
>
> % for aa in [a-c]; do echo $aa; done
> c
>
> ... In the last 'for' it wants to find files whereas in the previous it
> knows it's looking at text.  Could the previous be done on one line?  That
> is, the range '[a-c]' would be understood to be just text, not a file
> glob?
>


-- 
Mark J. Reed <[email protected]>