use bstr::{BStr, BString, ByteSlice, ByteVec}; /// Transforms the given `value` to be suitable for use as an argument for Bourne shells by wrapping it into single quotes.////// Every single-quote `'` is escaped with `\'`, every exclamation mark `!` is escaped with `\!`, and the entire string is enclosed/// in single quotes.pub fn single(mut value: &BStr) -> BString {    let mut quoted = BString::new(b"'".to_vec());     while let Some(pos) = value.find_byteset(b"'!") {        quoted.extend_from_slice(&value[..pos]);        quoted.push_str(b"'\\");        quoted.push(value[pos]);        quoted.push(b'\'');         value = &value[pos + 1..];    }     quoted.extend_from_slice(value);    quoted.push(b'\'');    quoted}