# Back up a folder with BACKUP() and RESTORE(), and run commands with SHELL()

> Pack a directory into one file and unpack it again with BACKUP() and RESTORE(), and run a shell command in the project folder with SHELL().

Framework: total5
Product: Total.js 5 (total5@0.0.19)
Language: en
Content-SHA256: 951ae399addf9763c314144b8f259adde20d5bd8d856698108de9e75dce43fde
Snapshot: c0700e321579725c5cf4f5ace1ad7d2866d1b4f93c24a63c0b41b6b7998e976c
Sources: total5-installed@total5@0.0.19
Review: not-recorded

- `BACKUP(filename, directory, [callback], [filter])` packs a directory (with its subdirectories) into **one file** and resolves with `{ filename, files, size }`. An existing file with that name is replaced. Without a callback it returns a promise.
- `RESTORE(filename, directory, [callback], [filter])` unpacks a file made with `BACKUP()` into a directory, creating the folders it needs, and resolves with `{ files, size, path }`.
- `SHELL(command, [callback], [cwd])` runs a shell command and resolves with its output (`stdout`). The folder is the one of the project, or the text you pass as the last argument. When the command fails the promise is rejected with an error whose `code` is the exit code. With a callback it is called as `callback(err, stdout, stderr)`.

`SHELL()` runs **exactly the text you give it**: never build the command from what a user sent.

```js controllers/backups.js
const Fs = require('fs');
const Path = require('path');

exports.install = function() {
	ROUTE('GET /backup/', backup);
	ROUTE('GET /shell/', shell);
};

async function backup($) {

	// a folder with a file and a subfolder
	const source = PATH.tmp('source');
	Fs.rmSync(source, { recursive: true, force: true });
	Fs.mkdirSync(Path.join(source, 'sub'), { recursive: true });
	Fs.writeFileSync(Path.join(source, 'a.txt'), 'hello');
	Fs.writeFileSync(Path.join(source, 'sub', 'b.txt'), 'world');

	const file = PATH.tmp('folder.backup');
	const packed = await BACKUP(file, source);

	const target = PATH.tmp('restored');
	Fs.rmSync(target, { recursive: true, force: true });
	const unpacked = await RESTORE(file, target);

	$.json({
		packed: [packed.files, packed.filename === file, Fs.existsSync(file)],
		unpacked: [unpacked.files, unpacked.size, unpacked.path === target],
		content: [Fs.readFileSync(Path.join(target, 'a.txt'), 'utf8'), Fs.readFileSync(Path.join(target, 'sub', 'b.txt'), 'utf8')]
	});
}

async function shell($) {

	const output = await SHELL('echo hello');
	const where = await SHELL('pwd', PATH.tmp());

	let code = null;
	try {
		await SHELL('exit 3');
	} catch (e) {
		code = e.code;
	}

	SHELL('echo from callback', (err, stdout) => $.json({ output: output, where: where.trim() === PATH.tmp() || where.trim().endsWith('/tmp'), code: code, callback: stdout }));
}
```