Ion supports two forms of process expansions: string-based process expansions ($()) that are commonly found in POSIX shells, and array-based process expansions (@()), a concept borrowed from the Oil shell. Where a string-based process expansion will execute a command and return a string of that command's standard output, an array-based process expansion will split the output into an array delimited by whitespaces.
let string = $(cmd args...) let array = [ @(cmd args...) ]
mkdir -p _tmp _tmp/t1 _tmp/t2 cd _tmp let res = $(ls) let res2 = [ @(ls) ] echo $res # output the string echo @res2 # output the array cd .. rm -fr _tmp
t1 t2 t1 t2