Efficient info command, interoperable man command

info-man.bash

#!/usr/bin/env bash

# All my gist code is licensed under the terms of the MIT license.

# Video demo: https://www.youtube.com/watch?v=ISKzBlzXRWE

# Add this to your .bashrc:

# get the texinfo node for a command
# - takes a command name, like 'cat'
# - if it belongs to a texinfo node, returns the node name, like 'coreutils' 
# - otherwise returns empty string
function __get_texinfo_node_for_command () {
  local coreutils_commands=(
    'cat' 'tac' 'nl' 'od' 'base32' 'base64' 'base64' 'basenc'
    'fmt' 'pr' 'fold' 
    'head' 'tail' 'split' 'csplit'  
    'wc' 'sum' 'cksum' 'b2sum' 'md5sum' 'sha1sum'    
    'sha224sum' 'sha256sum' 'sha384sum' 'sha512sum'
    'sort' 'shuf' 'uniq' 'comm' 'ptx' 'tsort' 'ptx'
    'cut' 'paste' 'join'
    'tr' 'expand' 'unexpand'
    'ls' 'dir' 'vdir' 'dircolors'
    'cp' 'dd' 'install' 'mv' 'rm' 'shred'
    'link' 'ln' 'mkdir' 'mkfifo' 'mknod' 'readlink' 'rmdir' 'unlink'
    'chown' 'chgrp' 'chmod' 'touch'
    'df' 'du' 'stat' 'sync' 'truncate'
    'echo' 'printf' 'yes'
    'false' 'true' 'test' 'expr' 'tee'
    'basename' 'dirname' 'pathchk' 'mktemp' 'realpath'
    'pwd' 'stty' 'printenv' 'tty'
    'id' 'logname' 'whoami' 'groups' 'users' 'who'
    'arch' 'date' 'nping' 'uname' 'hostname' 'hostid' 'uptime'
    'chcon' 'runcon'
    'chroot' 'env' 'nice' 'nohup' 'stdbuf' 'timeout'
    'kill' 'sleep'
    'factor' 'numfmt' 'seq' 
  )

  local bash_builtins=(
    '.' ':' '[' 'alias' 'bg' 'bind' 'break' 'builtin' 'caller' 'cd' 'command'
    'compgen' 'complete' 'compopt' 'continue' 'declare' 'dirs' 'disown' 'echo'
    'enable' 'eval' 'exec' 'exit' 'export' 'false' 'fc' 'fg' 'getopts' 'hash'
    'help' 'history' 'jobs' 'kill' 'let' 'local' 'logout' 'mapfile' 'popd'
    'printf' 'pushd' 'pwd' 'read' 'readarray' 'readonly' 'return' 'set'
    'shift' 'shopt' 'source' 'suspend' 'test' 'times' 'trap' 'type' 'typeset'
    'ulimit' 'umask' 'unalias' 'unset' 'wait'

    # and some reserved words too:
    '!' # this represents pipelines
    '[[' '{' 'case' 'if' 'for' 'function' 'select' 'time' 'until' 'while'
  )
  
  for cmd in "${bash_builtins[@]}"; do
    if [[ "$1" == "$cmd" ]]; then
      echo 'bash'
      return 0
    fi
  done
  for cmd in "${coreutils_commands[@]}"; do
    if [[ "$1" == "$cmd" ]]; then
      echo 'coreutils'
      return 0
    fi
  done

  echo ''
  return 0
}

# custom info
# - prepend 'coreutils' if argument is a coreutils command
# - prepend 'bash' if argument is a bash builtin
# - add some default options
function info () {
  # if there is only one non-option argument, and it matches a coreutils or
  # bash builtin, prepend the corresponding name
  local option_args=()
  local non_option_args=()
  for arg in "$@"; do
    if [[ ! "$arg" =~ ^- ]]; then
      non_option_args+=("$arg")
    else
      option_args+=("$arg")
    fi
  done
  if [[ "${#non_option_args[@]}" -eq 1 ]]; then
    info_node="$(__get_texinfo_node_for_command "${non_option_args[0]}")"
    if [[ -n "$info_node" ]]; then
        non_option_args=("${info_node}" "${non_option_args[@]}")
    fi
  fi

  # add default options and run
  option_args+=('--vi-keys' '--init-file' "${XDG_CONFIG_HOME}/infokey")
  command info "${option_args[@]}" "${non_option_args[@]}"
}
alias i="info"

# custom man
# - if receiving a command with info page, run info instead
function man () {
  if [[ "$#" -eq 1 && $(__get_texinfo_node_for_command "$1") != '' ]]; then
    info "$1"
  else
    command man "$@"
  fi
}
alias m="man"