# generate something random to make an attacker's job harder
pipe=$(uuidgen)
 
# use that randomly-generated sigil in place of | in our array
cmd_array=(
  ls -a /
  "$pipe" grep "home"
)
 
exec_array_pipe() {
  local arg cmd_q
  local -a cmd=( )
  while (( $# )); do
    arg=$1; shift
    if [[ $arg = "$pipe" ]]; then
      # log an eval-safe copy of what we're about to run
      printf -v cmd_q '%q ' "${cmd[@]}"
      echo "Starting pipeline component: $cmd_q" >&2
      # Recurse into a new copy of ourselves as a child process
      "${cmd[@]}" | exec_array_pipe "$@"
      return
    fi
    cmd+=( "$arg" )
  done
  printf -v cmd_q '%q ' "${cmd[@]}"
  echo "Starting pipeline component: $cmd_q" >&2
  "${cmd[@]}"
}
 
exec_array_pipe "${cmd_array[@]}"

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