Package-manager-like tool for commands, memba?

memba.sh

#!/usr/bin/env bash
#
# Memba - A "package manager" for global and local commands.
#
# Follows the suggested exit code range of 0 & 64-113 from http://www.tldp.org/LDP/abs/html/exitcodes.html
#
# | Exit Code | Meaning |
# |    ---    |   ---   |
# |    64     |  Error -- no command |
# |    65     |  Error -- unknown command |
# |    66     |  Error -- no target pattern for remove/rm/- or remove-all/rma |
# |    67     |  Error -- no command for add/+ |
# |    67     |  Error -- command already exists |

set -e # Enable "exit on first error"

#--------------------------------------------
# Utility functions memba?
#


# Based on https://stackoverflow.com/a/3232082/7665043

confirm() {
  # call with a prompt string or use a default
  read -r -p "${1:-Are you sure? [y/N]} " response
  case "$response" in
    [yY][eE][sS]|[yY]) 
      echo 0
    ;;
    *)
      echo 1
    ;;
  esac
}

# Based on https://stackoverflow.com/a/3951175/7665043
function isNumber () {
  case $1 in
    ''|*[!0-9]*) echo 1 ;;
    *) echo 0 ;;
  esac
}

function joinArray () {
  echo "${@}"
}

# Based on https://stackoverflow.com/a/17841619/7665043
function joinBy {
  local d=$1
  shift
  echo -n "$1"
  shift
  printf "%s" "${@/#/$d}"
}

# Based on https://stackoverflow.com/a/39463371/7665043
expand-q () {
  for i; do
    printf "%s " "${i@Q}"
  done
  echo
} 


#--------------------------------------------
# Functions, memba?
#

function membaUsage () {
  echo "Don't you memba...?"
}

function membaAdd () {
  local membaConfig="$1"
  local exists="false"
  shift

  [[ "$1" == "" ]] && echo "There must be a commands provided as a non-empty string provided for add/+." && membaUsage && exit 67

  [[ $(grep -c "^$1$" "$membaConfig") != "0" ]] && exists="true"
  [[ "$exists" == "true" ]] && echo "\"$1\" already exists, memba?" && exit 68

  while [[ "$#" -gt 0 ]]; do
    echo "${@}" >> "$membaConfig"
    shift
  done
}

function membaList () {
  local membaConfig="$1"
  shift

  if [[ "$#" -ne 0 ]]; then
    local pattern="$1"
    grep "$pattern" "$membaConfig"
  else
    cat "$membaConfig"
  fi
}

function membaListNumbered () {
  membaList "$@" | nl -n ln -w 1 -s " "
}

function membaChoice () {
  local membaConfig="$1"
  local pattern
  local choicesMemba
  local choicesLen
  local inp
  local choiceMessage
  local chosen
  local membad
  local target

  shift
  target=$(joinArray "${@}")

  choicesMemba=$(membaListNumbered "$membaConfig" "$@")
  choicesLen=$(echo "$choicesMemba" | tail -n 1 | awk '{ print $1 }')

  [[ "$choicesLen" -eq 0 ]] && echo "There's no commands with \"$target\", memba?" && exit 0

  membad=$(if [[ "$target" != "" ]]; then
    printf "I memba %sx command" "$choicesLen"
    [[ "$#" -gt 1 ]] && printf "s"
    echo " with \"$target\"."
  else
    printf "I memba %sx command" "$choicesLen"
    [[ "$#" -gt 1 ]] && printf "s"
    echo "."
  fi)

  choiceMessage=$(echo -e "$membad\n--------\n$choicesMemba\n\n--------\nChoose a command by number or 0 to cancel, memba?\nChoice: ")

  while [[ -z "$inp" || $(isNumber "$inp") -eq 1 || "$inp" -lt 0 || "$inp" -gt $choicesLen ]]; do
    clear > "$(tty)"
    [[ "$inp" != "" ]] && echo -e "$inp is not a choice, memba?\n"
    read -r -p "$choiceMessage" inp
    inp=$(echo "$inp" | tr -d '[:space:]')
  done

  if [[ "$inp" -ne 0 ]]; then
    chosen=$(echo "$choicesMemba" | awk '$1 == inp { for(i=2;i<=NF;++i) print $i }' inp="$inp" | tr '\n' ' ')
  else
    chosen="cancel"
  fi

  if [[ "$chosen" != "cancel" ]]; then
    $chosen || echo "That command is broken, memba?"
  fi
}

function membaRemove () {
  local membaConfig="$1"
  local matches
  local count=0
  local target
  local message
  local newConfig

  shift
  target=$(joinArray "${@}")

  [[ "$target" == "" ]] && echo "There must be a pattern provided as a non-empty string for remove-all/rma, memba?" && membaUsage && exit 66

  matches=$(grep "$target" "$membaConfig")
  count=$(grep -c "$target" "$membaConfig")

  [[ "$count" -lt 1 ]] && echo "No, I don't memba \"$target\".." && exit 68

  message=$(echo -e "Are you sure you want to remove all commands containing \"$target\"?\n${matches}\n[y/N], memba?:")

  echo "I memba ""$count""x command"
  [[ "$#" -gt 1 ]] && printf "s"
  " with \"$target\"."

  if [[ "$count" -ne 0 && $(confirm "$message") -eq 0 ]]; then
    newConfig=$(awk '!/'"$target"'/ { print }' < "$membaConfig")
    [[ "$newConfig" == "" ]] && printf "" > "$membaConfig" || echo "$newConfig" > "$membaConfig"
  fi
}

#--------------------------------------------
# Parse args and run, memba!?
#


function runScript () {
  local membaConfig="$HOME/.memba"

  if [[ "$#" -eq 0 ]]; then
    # Display usage..
    echo "This needs a command, memba?"
    membaUsage
    exit 64
  else
    local option="$1"

    shift

    case $option in
      "add" | "+" )
        membaAdd "$membaConfig" "$@"
      ;;
      "choice" | "ch" | "?" )
        membaChoice "$membaConfig" "$@"
      ;;
      "list" | "ls" | "." )
        membaList "$membaConfig" "$@"
      ;;
      "remove" | "rm" | "-" )
        membaRemove "$membaConfig"  "$@"
      ;;
      * )
        echo "Unknown command \"$option\", memba?"
        membaUsage
        exit 66
    esac
  fi
}

calledWith=$(expand-q $(ps -o args= $$ | awk '{ for(i=4;i<=NF;++i) print $i }' ))
echo "$calledWith"
runScript "$@"