A small bash script to compile an assembly code into an elf

asm2elf.sh

#!/bin/bash

function usage() {
	echo -n "Usage: "
	echo "$0 <input_file> [<output_file>]"
	echo;
}

function help() {
	echo "$0 - A simple program to compile an assembly file into an elf."
	usage
}

function checkfirst() {
	if [[ ! -f "$1" ]]; then
		echo "$1 doesn't exist."
		exit 1
	fi
	if [[ "$1" == "-h" ]] || [[ "$1" == "--help" ]]; then
		help
		exit 0
	fi
}

_in=""
_out=""
if [[ $# == 1 ]]; then
	checkfirst "$1"
	_in="$1"
	_out=$(echo "$1" | cut -d '.' -f 1)
elif [[ $# == 2 ]]; then
	checkfirst "$1"
	_in="$1"
	_out="$2"
else
	echo "Invalid arguments provided."; echo
	usage
	exit 1
fi

gcc -static -nostdlib -o "$_out" "$_in"

sample.S

.global _start
_start:
.intel_syntax noprefix
	mov rax, 60
	syscall