far-shell.sh

#!/usr/bin/env bash

## setup parameters
app_name='far-shell'
debug_mode='0'

## basic setup tools
msg() {
    printf '%b\n' "$1" >&2
}

success() {
    if [ "$ret" -eq '0' ]; then
        msg "\e[32m[✔]\e[0m ${1}${2}"
    fi
}

error() {
    msg "\e[31m[✘]\e[0m ${1}${2}"
    exit 1
}

debug() {
    if [ "$debug_mode" -eq '1' ] && [ "$ret" -gt '1' ]; then
        msg "An error occurred in function \"${FUNCNAME[$i+1]}\" on line ${BASH_LINENO[$i+1]}, we're sorry for that."
    fi
}

program_exists() {
    local ret='0'
    type $1 > /dev/null 2>&1 || { local ret='1'; }

    # throw error on non-zero return value
    if [ ! "$ret" -eq '0' ]; then
        error "$2"
    fi
}

# setup functions

## main
msg "Welcome to $app_name!"