# shell-quote [![Version Badge][npm-version-svg]][package-url]

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Parse and quote shell commands.

# example

## quote

```js
var quote = require('shell-quote/quote');
var s = quote([ 'a', 'b c d', '$f', '"g"' ]);
console.log(s);
```

output

```
a 'b c d' \$f '"g"'
```

## parse

```js
var parse = require('shell-quote/parse');
var xs = parse('a "b c" \\$def \'it\'\\\'\'s great\'');
console.dir(xs);
```

output

```
[ 'a', 'b c', '$def', "it's great" ]
```

## parse with an environment variable

```js
var parse = require('shell-quote/parse');
var xs = parse('beep --boop="$PWD"', { PWD: '/home/robot' });
console.dir(xs);
```

output

```
[ 'beep', '--boop=/home/robot' ]
```

## parse with custom escape character

```js
var parse = require('shell-quote/parse');
var xs = parse('beep ^--boop="$PWD"', { PWD: '/home/robot' }, { escape: '^' });
console.dir(xs);
```

output

```
[ 'beep', '--boop=/home/robot' ]
```

## parse with unquoted variable splitting

```js
var parse = require('shell-quote/parse');
var xs = parse('a $T', { T: 'c d' }, { splitUnquoted: true });
console.dir(xs);
```

output

```
[ 'a', 'c', 'd' ]
```

## parsing shell operators

```js
var parse = require('shell-quote/parse');
var xs = parse('beep || boop > /byte');
console.dir(xs);
```

output:

```
[ 'beep', { op: '||' }, 'boop', { op: '>' }, '/byte' ]
```

## parsing shell comment

```js
var parse = require('shell-quote/parse');
var xs = parse('beep > boop # > kaboom');
console.dir(xs);
```

output:

```
[ 'beep', { op: '>' }, 'boop', { comment: ' > kaboom' } ]
```

# methods

```js
var quote = require('shell-quote/quote');
var parse = require('shell-quote/parse');
```

## quote(args)

Return a quoted string for the array `args` suitable for using in shell
commands.

Each entry of `args` may be a string, or one of the object shapes that
`parse` emits: `{ op }` (where `op` is one of the control operators
`||`, `&&`, `;;`, `|&`, `<(`, `<<<`, `>>`, `>&`, `<&`, `&`, `;`, `(`,
`)`, `|`, `<`, `>`), `{ op: 'glob', pattern }`, or `{ comment }`. Any
other object shape, an unrecognized `op`, or a `pattern`/`comment`
containing line terminators throws a `TypeError`.

The output is POSIX shell (`sh`/`bash`) quoting.
It is not valid for Windows `cmd.exe` or PowerShell,
whose rules differ and, for `cmd.exe`,
are not solvable in the general case. On Windows,
do not build a shell command string from this output;
instead pass an argument array to a non-shell API such as
`child_process.execFile` or `spawn`
(or the `cross-spawn` package),
which does no shell parsing and needs no quoting.

Use the returned string verbatim as shell input.
It is already a complete, escaped shell word (or words);
do not wrap it in additional quotes or embed it in `eval '...'`.
Re-quoting the output (for example, placing it inside single quotes)
turns its backslash escapes into literal characters and corrupts the value.

## parse(cmd, env={})

Return an array of arguments from the quoted string `cmd`.

Interpolate embedded bash-style `$VARNAME` and `${VARNAME}` variables with
the `env` object which like bash will replace undefined variables with `""`.

By default an expanded variable is a single token even when unquoted.
Pass `{ splitUnquoted: true }` to split an unquoted expansion into multiple tokens the way a shell performs field splitting,
using the default `IFS` (space, tab, newline).
Pass a string to use its characters as the `IFS` instead
(for example `{ splitUnquoted: ':' }`).
A quoted expansion (`"$VAR"`) is never split.

Only simple `$VARNAME` and `${VARNAME}` interpolation is supported.
Bash parameter expansion beyond a plain variable name is not evaluated:
forms such as array subscripts (`${arr[i]}`), length (`${#arr[@]}`),
and modifiers (`${var:-default}`, `${var/a/b}`)
are treated as an unknown variable and expand to `""`,
while arithmetic (`$((...))`) and command substitution (`$(...)`)
are not interpreted.
Whitespace inside `${...}` throws a `Bad substitution` error.

`env` is usually an object but it can also be a function to perform lookups.
When `env(key)` returns a string, its result will be output just like `env[key]` would.
When `env(key)` returns an object, it will be inserted into the result
array like the operator objects.

When a bash operator is encountered,
the element in the array with be an object with an `"op"` key set to the operator string.
For example:

```
'beep || boop > /byte'
```

parses as:

```
[ 'beep', { op: '||' }, 'boop', { op: '>' }, '/byte' ]
```

# install

With [npm](http://npmjs.org) do:

```
npm install shell-quote
```

# license

MIT

[package-url]: https://npmjs.org/package/shell-quote
[npm-version-svg]: https://versionbadg.es/ljharb/shell-quote.svg
[deps-svg]: https://david-dm.org/ljharb/shell-quote.svg
[deps-url]: https://david-dm.org/ljharb/shell-quote
[npm-badge-png]: https://nodei.co/npm/shell-quote.png?downloads=true&stars=true
[license-image]: https://img.shields.io/npm/l/shell-quote.svg
[license-url]: LICENSE
[downloads-image]: https://img.shields.io/npm/dm/shell-quote.svg
[downloads-url]: https://npm-stat.com/charts.html?package=shell-quote
[codecov-image]: https://codecov.io/gh/ljharb/shell-quote/branch/main/graphs/badge.svg
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