pyenv/libexec/rbenv-exec

#!/usr/bin/env bash
#
# Summary: Run an executable with the selected Ruby version
#
# Usage: rbenv exec <command> [args...]
#
# Runs an executable contained by the currently selected Ruby's bin
# directory. Rough equivalent of:
#
#   exec "$(rbenv prefix)/bin/$command" args...

set -e
[ -n "$RBENV_DEBUG" ] && set -x

rubypath=""
# Provide rbenv completions
while true; do
  case "$1" in
  "--complete" )
    exec rbenv shims --short
    ;;
  "--rubypath" )
    rubypath=1
    shift 1
    ;;
  * )
    break
    ;;
  esac
done

# Replace any "RBENV_ROOT/shims" or "RBENV_ROOT/versions/*/bin" paths in the
# list with the given path. If no replacements were made, prepend the path onto
# the list.
replace_shims_path() {
  local path="$1"
  local dir="$2"
  # fake directory that serves as a placeholder for shims location in RUBYPATH:
  local placeholder="/rbenv_shims_were_here"
  local found=""
  local result=""
  local -a paths
  IFS=: paths=($path)

  for path in "${paths[@]}"; do
    if [[ $path = "${RBENV_ROOT}/shims" || $path == "${RBENV_ROOT}/versions/"*/bin || $path = $placeholder ]]; then
      found=1
      result="${result}${dir:-$placeholder}:"
    else
      result="${result}${path}:"
    fi
  done

  # if no rbenv paths were replaced, simply prepend the path
  [ -n "$found" -o -z "$dir" ] || result="${dir}:${path}"
  echo "${result%:}"
}

RBENV_VERSION="$(rbenv-version-name)"
RBENV_COMMAND="$1"

if [ -z "$RBENV_COMMAND" ]; then
  rbenv-help --usage exec >&2
  exit 1
fi

export RBENV_VERSION
RBENV_COMMAND_PATH="$(rbenv-which "$RBENV_COMMAND")"

OLDIFS="$IFS"
IFS=$'\n' scripts=(`rbenv-hooks exec`)
IFS="$OLDIFS"
for script in "${scripts[@]}"; do
  source "$script"
done

shift 1
if [ -n "$rubypath" ]; then
  bindir=""
  [ "$RBENV_VERSION" != "system" ] && bindir="${RBENV_COMMAND_PATH%/*}"
  export RUBYPATH="$(replace_shims_path "${RUBYPATH:-$PATH}" "$bindir")"
fi
exec -a "$RBENV_COMMAND" "$RBENV_COMMAND_PATH" "$@"