Functions which i need in my bash scripts but could also be nice for other ones

debian-bash-helper-functions.sh

#!/bin/bash
# CSoellinger
######################################################
# Function Vars
APT_INSTALL="apt-get install -yqqq"
APT_UPDATE="apt-get update -yqqq"
NPM_INSTALL="npm --loglevel=silent install -g"

TEXT_DONE="DONE"
TEXT_WAITING_DOTS="... "
######################################################
# Echos
_echo() { echo -e "$1"; }
_echo_not_root() { _echo_and_exit "ERROR: You have to be root to execute this script"; }
_echo_root() { _echo_and_exit "ERROR: Do not execute this script as root user"; }
_echo_exec_start() { echo -ne "${1}${TEXT_WAITING_DOTS}"; }
_echo_exec_end() { echo -e "${TEXT_DONE}"; }
_echo_exec() { _echo_exec_start "$1"; $2; _echo_exec_end; }
_echo_and_exit() {
    [ "$2" == "" ] && EXIT_NR="1" || EXIT_NR="$2"

    echo -e "$1"
    exit $EXIT_NR
}

_apt_install() { _echo_exec_start "$1"; $APT_INSTALL $2 2>&1 >/dev/null; _echo_exec_end; }
_apt_update() { _echo_exec_start "Updating apt"; $APT_UPDATE 2>&1 >/dev/null; _echo_exec_end; }
_npm_install() { _echo_exec_start "$1"; $NPM_INSTALL $2; _echo_exec_end; }

_command_exists() { type "$1" &> /dev/null ; }

_fetch_bashrc_name() {
    SHELLPATH="$SHELL"
    case "${SHELLPATH##*/}" in
        zsh )
            echo ".zshrc";;
        bash )
            echo ".bashrc";;
    esac
    exit 0
}

_chown_recursive_from_target() {
    [ ! "$1" ] && exit 0

    TARGET_OWNER=`ls -ld $NVM_DIR | awk '{print $3}'`

    chown $TARGET_OWNER:$TARGET_OWNER $1 -R
}

_is_online() {
    if ping -w 1 -i 0.2 8.8.8.8 > /dev/null; then
        echo "ONLINE"
    else
        if [ `_is_online_resolve_hostname` ]; then
            echo "ONLINE"
        #else
        #    echo "OFFLINE"
        fi
    fi
    exit 0
}

_is_online_resolve_hostname() {
    if ! _command_exists host; then exit 0; fi

    if 2>&1 host -h | grep -q -- -W; then command="host -W 1"; else command="host -s 1"; fi

    if $command google-public-dns-a.googxxle.com > /dev/null; then
        echo "ONLINE"
    #else
    #    echo "OFFLINE"
    fi
    exit 0
}

_is_composer_installed() {
    composer -v > /dev/null 2>&1
    echo $?
    exit 0
}

_exit_if_not_root() { [ $EUID != 0 ] && _echo_not_root; }
_exit_if_root() { [ $EUID == 0 ] && _echo_root; }
######################################################
# Function "alias"..
_e() { _echo "$1"; }
_nl() { _echo ""; }

_not_root() { _echo_not_root; }

_exit() { _echo_and_exit $1; }

_exec_start() { _echo_exec_start "$1"; }
_exec_end() { _echo_exec_end; }
_exec() { _echo_exec "$1" "$2"; }

_cmd_exists() { _command_exists $1; }