Function shell_quote 

pub fn shell_quote(value: &str) -> String

value as a single POSIX shell word.

Two places need this and they must not answer it differently: the hook command a consumer renders into HOOKS_MANIFEST_TEMPLATE is executed by a shell, and the recovery commands manager::PluginManager::manual_commands prints are copied into one. A home directory containing a space is ordinary, and either use getting it wrong silently changes the arguments — the executed hook runs against the wrong path, the pasted command registers the wrong directory.

Quoting is applied only when the value needs it, so ordinary paths and plugin specs print bare. The safe set is a deliberately short allowlist — ASCII alphanumerics plus ._-/@:+,= — every member of which a POSIX shell leaves alone in a non-leading word. Everything else, including the empty string, is wrapped in single quotes, which suppress every expansion the shell performs; the only character then needing care is the closing quote itself, spliced out, escaped, and spliced back in.