Bash

Script

$ type script
$ chmod +x script
$ ./script
$ .script
$ source script
$ bash script

#!/bin/bash

Command Line

Everything is a file
255 Byte
On Linux: The maximum length for a file name is 255 bytes.
The maximum combined length of both the file name and path name is 4096 bytes. 
This length matches the PATH_MAX that is supported by the operating system.