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sed-in-place

A deny rule by default: it refuses sed -i, whose two spellings destroy each other's work across platforms, and names what to run instead.

What it catches

sed -i, whose two spellings destroy each other's work across platforms.

Why

sed -i is not portable and the two spellings destroy each other's work. GNU reads sed -i 's/x/y/' f as an edit; BSD and macOS read that same script as the BACKUP SUFFIX and take the next argument as the script. sed -i '' ... is the macOS spelling and makes GNU edit nothing. So a command that works here mangles the file on the next machine, by WRITING, before anyone reads a diff. An editor tool reads the file first and reports what it changed, and for a whole-tree rename magus refs <symbol> --occurrences gives column-precise sites a pattern cannot. Reading with sed is untouched.

Default and override

By default this rule takes the decision deny. A workspace sets it by name, in its root magusfile, to deny, advise or off:

magus\guard.builtins({"sed-in-place": "advise"})

A loosening takes effect once it is committed; a tightening applies at once.

Seeing it

A verdict names its rule in brackets, which is how you got here:

deny [sed-in-place]: ...

A workspace that sets this rule to advise sees advise [sed-in-place]: ... instead.

magus describe rule sed-in-place prints the same entry at a terminal, and magus describe rules lists every rule this workspace enforces.

See also

guardrulessed-in-placedeny
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Glossary

Workspace

The magus root directory that owns a set of projects and shared config; the unit magus operates over. Workspace in full.

Magusfile

The magusfile.buzz that declares a project's targets (as export funs) and binds its spells. Magusfile in full.

Spell

A language/runtime adapter (e.g. go, md) that maps generic targets onto a toolchain's real commands. Spell in full.

Buzz

The language magusfiles are written in (the .buzz engine). Buzz in full.

CI

An ordinary target you compose yourself with ctx.needs; magus does not hardcode its stages. It is the anchor magus affected ci keys off, and ci strips the rw charm. CI in full.

Agent

A model working through an agent host such as Claude Code, Codex, Cursor or OpenCode. magus treats an agent as one more caller of its CLI, MCP tools and console, held to the same checks as a person. Agent in full.

Tool

An action a model can call through its host: a name, a description, a typed input and a result. magus serves its tools over MCP, each a read of the workspace model or a run of the CLI it already has. Tool in full.

Run

One target executing under one magus invocation, such as magus run test web or magus affected ci. A run keeps its captured output behind an output reference. Every magus run is a run whether or not any job asked for it; see Job for how the two relate. Run in full.

Conventions

Placeholders

Angle brackets mark a value you replace with your own; never type the brackets:

magus run <target>
magus completion <shell>    # e.g. bash, zsh, fish

<target>, <path>, <shell>, <name> and the like are stand-ins, not literal text.