Expanding a brace expansion string held in a variable for use in a for loop?

Question

I've got the following script:

FOOS=foo{1..5}
for i in `echo $FOOS` do
echo bar
done

Now I (think I) get the idea that the brace expansion only works with literals - hence the echo - but all this seems to do is print just one bar to the console. Why (is string/brace expansion not working)?

What I'd expect to happen is:

1. Assign the string (foo{1..5}) representing an expansion to variable FOOS
2. substitute $FOOS, so I've basically got for i in 'echo foo{1..5}' do (looks like I can't escape back-ticks here)
3. execute echo, so I now have for i in foo1 foo2 foo3 foo4 foo5 do
4. execute for, printing bar five times to the console output
5. Not get just one bar printed on screen as the only output :-)

• Mikel: Your first line doesn't work. $ FOOS = foo{1..5} FOOS: command not found. Please fix and provide the script exactly as is.
• Mingye Wang: paste your script onto shellcheck.net and click the arrow.

Answer 1

1.

FOO=$(echo foo{1..5})

but better is to use an array

FOO=(foo{1..5})

2.

echo ${FOO[*]}

4.

for i in {1..5}
do
 echo bar
done

or

for i in $(seq 5)
do
 echo bar
done

• Mingye Wang: Just use FOO=( {1..5} )。
• Giszmo: What am I doing wrong? v=$( echo {1,20{0..3}} ); echo $v yields 1 200 201 202 203 yet v=( {1,20{0..3}} ); echo $v yields only 1. Answer: Use echo ${v[*]}!