Task runner (Makefile Replacement). Pure bash (shell) functions based tasks. Autocomplete (completion) for both bash and zsh

.bashrc

_task() {
  TASKS=$(./tasks.sh ls-func)
  local -a LIST=()
  while IFS='' read -r line; do LIST+=("$line"); done < <(compgen -W "$TASKS")
}

complete -F _task task

.zshrc

_task() {
  TASKS=$(./tasks.sh ls-func)
  local -a LIST=()
  while IFS='' read -r line; do LIST+=("$line"); done < <(compgen -W "$TASKS")
  compadd -a LIST
}

compdef _task task -default-

tasks.sh

#!/bin/bash

# Makefile Replacement with Pure Bash Function

# Strict mode: http://redsymbol.net/articles/unofficial-bash-strict-mode/
set -euo pipefail

task1() {
  echo "task1"
}

task2() {
  task1
  echo "task2"
}

task3() {
  task1
  task2
  echo "task3"
}

get-func-list() {
	env -i bash --noprofile --norc -c '
    source "'"$1"'"
    typeset -f |
    grep '\''^[^{} ].* () $'\'' |
    awk "{print \$1}" |
    while read -r fcn_name; do
        type "$fcn_name" | head -n 1 | grep -q "is a function$" || continue
        echo "$fcn_name"
    done
'
}

ls-func() {
	FUNC_LIST=""
	for fcn_name in $(get-func-list tasks.sh); do
		FUNC_LIST="$FUNC_LIST $fcn_name"
	done
	echo "$FUNC_LIST"
}

# Tries to run the parameter as a function: https://stackoverflow.com/a/16159057/3203441
"$@"