rshebang

Shebang

r[shebang.intro] A shebang is an optional line that is typically used in Unix-like systems to specify an interpreter for executing the file.

[!EXAMPLE]

#!/usr/bin/env rustx

fn main() {
    println!("Hello!");
}

r[shebang.syntax]

@root SHEBANG ->
    `#!` !((WHITESPACE | LINE_COMMENT | BLOCK_COMMENT)* `[`)
    ~LF* (LF | EOF)

r[shebang.syntax-description] The shebang starts with the characters #! and extends through the first U+000A (LF) or through EOF if no LF is present. If the #! characters are followed by [ (ignoring any intervening comments or whitespace), the line is not considered a shebang (to avoid ambiguity with an inner attribute).

r[shebang.position] The shebang may appear immediately at the start of the file or after the optional byte order mark.