ref: d5f416292a3ca7fb8e726487f34ac1f13d29e4a4
iron/libexec/main
#!/usr/bin/env bash
set -e
resolve_link() {
  $(type -p greadlink readlink | head -1) "$1"
}
abs_dirname() {
  local cwd="$(pwd)"
  local path="$1"
  while [ -n "$path" ]; do
    cd "${path%/*}"
    local name="${path##*/}"
    path="$(resolve_link "$name" || true)"
  done
  pwd
  cd "$cwd"
}
#libexec_path="$(abs_dirname "$0")"
sjalv=$(basename $0)
libexec_path=@prefix@/libexec/$sjalv
if [[ "${libexec_path}" = *"@"* ]]; then
        libexec_path="$(abs_dirname "$0")" #Substitution has not happened -> dev version
fi
export _SUB_ROOT="$(abs_dirname "$libexec_path")"
export PATH="${libexec_path}:$PATH"
command="$1"
case "$command" in
"" | "-h" | "--help" )
  exec sub-help
  ;;
* )
  command_path="$(command -v "sub-$command" || true)"
  if [ ! -x "$command_path" ]; then
    echo "sub: no such command \`$command'" >&2
    exit 1
  fi
  shift
  exec "$command_path" "$@"
  ;;
esac