Function upsert_managed_block 

pub fn upsert_managed_block(
    bin_name: &str,
    shell: Shell,
    file_path: &Path,
    block_body: &str,
) -> Result<()>

Inserts or replaces a managed shell configuration block in a startup file.

The managed block is identified by the binary name and shell, allowing repeat installs to update the same block instead of appending duplicates.

Arguments

• bin_name: Binary name used in the managed block markers.
• shell: Shell whose startup block is being inserted or replaced.
• file_path: Startup file to update.
• block_body: Shell-specific content placed between the managed markers.

Returns

Returns Ok(()) after the startup file has been written.