The `-i` flag with `sed` means "in-place", if you're curious; the use
thereof allows for making actual changes to the file, not just
superfluously, such as for additional parsing.
The `s///` is a simple substitution, wherein the `s` marks that it's a
substitution, the `/` marks the boundaries*, and the final boundary can
be suffixed with various flags, such as `g`, for global operations, -
and `i`, for case-insensitive operations.
* required, but the slash can switched for something else, if needed, -
such as `|`, which is commonly used for paths. For example:
`s|/path/to/file|/path/file|`