# Text / Byte-String Functions
String and byte-buffer manipulation — concatenation, length, encoding, and hex conversion.
## Index
### Functions
| [concat](#concat) | `bytes` | Concatenate strings |
| [crlflines](#crlflines) | `bytes` | join strings with CRLF line-endings |
| [len](#len) | `u64` | Return the length of a string (or strings) |
### Constants
| CRLF | `(bytes)"\r\n"` |
## concat
```resynth
resynth fn concat (
=>
*collect_args: bytes,
) -> bytes;
```
Concatenate strings
### Parameters
| `…` | `bytes` | Zero or more additional values |
### Returns
| `bytes` |
## crlflines
```resynth
resynth fn crlflines (
=>
*collect_args: bytes,
) -> bytes;
```
join strings with CRLF line-endings
### Parameters
| `…` | `bytes` | Zero or more additional values |
### Returns
| `bytes` |
## len
```resynth
resynth fn len (
=>
*collect_args: bytes,
) -> u64;
```
Return the length of a string (or strings)
### Parameters
| `…` | `bytes` | Zero or more additional values |
### Returns
| `u64` |