# `oo` Rewrite
> **Status: experimental** — the command set and output format may change
> without notice.
`oo rewrite` prints an `oo`-prefixed version of a shell command, for agent
hooks that need the rewritten form before execution. It never executes the
command and never reads from or writes to the output index store.
## Syntax
```sh
oo rewrite <command...>
```
If at least one shell segment (split on `&&`, `||`, `;`) matches an `oo`
pattern, the matching segments are prefixed with `oo` and the result is
printed on **stdout** with exit code **0**.
If no segment matches, nothing is printed and exit code is **1**.
A segment is rewritten when *any* pattern's `command_match` regex matches
*anywhere* in the segment text — patterns are unanchored, and quoted text is
not excluded from matching. This is the same matching semantics as
`oo <command>`, so `oo rewrite nope pytest -q` prints
`oo nope pytest -q`. Exit code 1 also covers the case where a pattern file
failed to load (patterns are loaded project, user, then builtin).
The rewritten output preserves the original text **byte-for-byte** except for
the inserted `oo ` prefix(es) and the canonical separator spacing. Internal
whitespace (double spaces, tabs), newlines inside quotes, and all other
characters are kept exactly as written. A segment is refused (exit 1) when
it contains an unquoted newline (a newline outside quotes is not a command
separator and joining lines would change semantics), or when a leading
`VAR=value` env token's value contains a quote or backslash (such a value
would need a full shell tokenizer to re-emit safely — the conservative
option is chosen).
## Examples
```sh
$ oo rewrite pytest -q
oo pytest -q
$ oo rewrite git status && pytest -q
git status && oo pytest -q
$ oo rewrite cargo test > log.txt
# (no output — redirections are refused)
exit 1
```
## Edge cases
- **Pipes** (`|`), **redirections** (`<`/`>`), **heredocs** (`<<`),
**command substitution** (`$()`/backticks), and **background** (`&`)
are not rewritten — `oo` can't safely reason about them, so exit 1.
- **`&&`, `||`, `;`** inside quotes are not segment separators.
- **Backslashes** outside single quotes escape the next character: an
escaped quote does not toggle quoting, `\&\&` is not a separator, and an
escaped `|`/`<`/`>`/`$()`/backtick is not refused. Inside single quotes a
backslash is literal. A trailing lone backslash or an unterminated quote
yields no rewrite (exit 1), since neither re-parses identically.
- **`VAR=value`** environment prefixes are preserved in front of `oo`.
An env value containing a quote or backslash is refused (exit 1) —
such a value would need a full shell tokenizer to re-emit safely, so
the conservative option is chosen.
- An **unquoted newline** inside a segment is refused (exit 1): a newline
outside quotes is not a command separator (only `&&`/`||`/`;` are), so
the segment spans multiple lines and joining them would change semantics.
Newlines inside quotes are preserved verbatim.
- Already-`oo`-prefixed segments are left as-is (no double-wrap).
- Commands longer than 16 KiB are refused (exit 1, no output) — the bound
caps worst-case regex work over the command string.