echo ff{c,b,a}
echo f{d,e,f}g
echo {l,n,m}xyz
echo {abc\,def}
echo {abc}

echo \{a,b,c,d,e}
echo {x,y,\{a,b,c}}
echo {x\,y,\{abc\},trie}

echo /usr/{ucb/{ex,edit},lib/{ex,how_ex}}

echo XXXX\{`echo a b c | tr ' ' ','`\}
eval echo XXXX\{`echo a b c | tr ' ' ','`\}

echo {}
echo { }
echo }
echo {
echo abcd{efgh

echo foo {1,2} bar
echo `zecho foo {1,2} bar`
echo $(zecho foo {1,2} bar)