Obtaining the delta for 'declare -F' between current and clean shell environments

Main question: how would one get the delta for declare -F, between that in the current shell, and that as if the shell just started (first two commands below). $(declare -F) does not solve the problem because the subshell is a copy of the shell process . Subsidiary: why does the third command below output nothing? $ exec env -i bash $ declare -F declare -f ShowInstallerIsoInfo declare -f __expand_tilde_by_ref declare -f __get_cword_at_cursor_by_ref declare -f __load_completion declare -f __ltrim_colon_completions declare -f __parse_options declare -f __reassemble_comp_words_by_ref declare -f _allowed_groups declare -f _allowed_users declare -f _available_interfaces declare -f _bashcomp_try_faketty declare -f _bq_completer declare -f _cd declare -f _cd_devices declare -f _command declare -f _command_offset declare -f _complete_as_root declare -f _completer declare -f _completion_loader declare -f _configured_interfaces declare -f _count_args declare -f _dvd_devices declare -f _expand declare -f _filedir declare -f _filedir_xspec declare -f _fstypes declare -f _get_comp_words_by_ref declare -f _get_cword declare -f _get_first_arg declare -f _get_pword declare -f _gids declare -f _have declare -f _included_ssh_config_files declare -f _init_completion declare -f _installed_modules declare -f _ip_addresses declare -f _kernel_versions declare -f _known_hosts declare -f _known_hosts_real declare -f _longopt declare -f _mac_addresses declare -f _minimal declare -f _modules declare -f _ncpus declare -f _open_files_for_editing declare -f _parse_help declare -f _parse_usage declare -f _pci_ids declare -f _pgids declare -f _pids declare -f _pnames declare -f _python_argcomplete declare -f _quote_readline_by_ref declare -f _realcommand declare -f _rl_enabled declare -f _root_command declare -f _service declare -f _services declare -f _shells declare -f _signals declare -f _split_longopt declare -f _sysvdirs declare -f _terms declare -f _tilde declare -f _uids declare -f _upvar declare -f _upvars declare -f _usb_ids declare -f _user_at_host declare -f _usergroup declare -f _userland declare -f _variables declare -f _xfunc declare -f _xinetd_services declare -f dequote declare -f quote declare -f quote_readline $ "$SHELL" -c 'declare -F' Other: $ uname -a Linux elitebook 6.7.3-arch1-2 #1 SMP PREEMPT_DYNAMIC Fri, 02 Feb 2024 17:03:55 +0000 x86_64 GNU/Linux $ bash --version GNU bash, version 5.2.26(1)-release (x86_64-pc-linux-gnu) $ echo $SHELL /bin/bash ## Update: > The clean state is an empty list of functions, as seen in the output of bash -c 'declare -F' Based on the first command I expected the second to output two functions rather than zero. $ grep -F -f I expected the second to output two functions rather than zero. Here might be the reason for sourcing not taking effect: $ cat ~/.bashrc # # ~/.bashrc # # If not running interactively, don't do anything [[ $- != *i* ]] && return Workaround does output two functions. $ bash -c 'source /dev/null