# Left Pad
> Left pad a string.
## Usage
```javascript
var lpad = require( '@stdlib/string/left-pad' );
```
#### lpad( str, len\[, pad] )
Left pads a `string` such that the padded `string` has a `length` of **at least** `len`.
```javascript
var str = lpad( 'a', 5 );
// returns ' a'
```
By default, an input `string` is padded with `spaces`. To pad with a different character or sequence of characters, provide a `pad` string.
```javascript
var str = lpad( 'beep', 10, 'b' );
// returns 'bbbbbbbeep'
str = lpad( 'boop', 12, 'beep' );
// returns 'beepbeepboop'
```
## Notes
- An output `string` is **not** guaranteed to have a length of **exactly** `len`, but to have a `length` of **at least** `len`. To generate a padded `string` having a `length` equal to `len`
```javascript
var str = lpad( 'boop', 10, 'beep' ); // => length 12
// returns 'beepbeepboop'
str = str.substring( str.length-10 ); // => length 10
// returns 'epbeepboop'
```
## Examples
```javascript
var round = require( '@stdlib/math/base/special/round' );
var randu = require( '@stdlib/random/base/randu' );
var lpad = require( '@stdlib/string/left-pad' );
var str = 'beep';
var n;
var i;
for ( i = 0; i < 100; i++ ) {
n = round( randu()*10 ) + str.length;
console.log( lpad( str, n, 'b' ) );
}
```
* * *
## CLI
### Usage
```text
Usage: lpad [options] [] --len=
Options:
-h, --help Print this message.
-V, --version Print the package version.
--len length Minimum string length.
--pad str String used to pad. Default: ' '.
--split sep Delimiter for stdin data. Default: '/\\r?\\n/'.
```
### Notes
- If the split separator is a [regular expression][mdn-regexp], ensure that the `split` option is either properly escaped or enclosed in quotes.
```bash
# Not escaped...
$ echo -n $'beep\nboop' | lpad -len 8 --split /\r?\n/
# Escaped...
$ echo -n $'beep\nboop' | lpad -len 8 --split /\\r?\\n/
```
- The implementation ignores trailing delimiters.
### Examples
```bash
$ lpad beep --len 10 --pad b
bbbbbbbeep
```
To use as a [standard stream][standard-streams],
```bash
$ echo -n 'beep' | lpad --len 8
beep
```
By default, when used as a [standard stream][standard-streams], the implementation assumes newline-delimited data. To specify an alternative delimiter, set the `split` option.
```bash
$ echo -n 'boop\tbeep' | lpad --len 8 --split '\t'
boop
beep
```
[standard-streams]: https://en.wikipedia.org/wiki/Standard_streams
[mdn-regexp]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions
[@stdlib/string/pad]: https://github.com/stdlib-js/string/tree/main/pad
[@stdlib/string/right-pad]: https://github.com/stdlib-js/string/tree/main/right-pad