pub fn command_word(segment: &str) -> Option<String>Expand description
Quote-aware command word of a command segment.
Tokenizes segment into words while respecting quotes and backslash
escapes, skips leading variable assignments (including quoted values
like FOO='hello world'), and returns the first non-assignment word,
unquoted (e.g. python for 'python' or "python"). Returns None when
the segment is empty or consists only of assignments.