---
source: tests/rule_docs.rs
expression: render_rule_doc(rule.as_ref())
---
## `deprecated-command`
Flag the obsolete two-letter font *switches* (`\bf`, `\it`, `\rm`, `\sf`, `\tt`, `\sc`, `\sl`) that LaTeX 2e superseded with the `\...series`/`\...shape`/`\...family` declarations. `\em` is not flagged; it is still the supported emphasis switch. The autofix swaps just the control word (`\bf` -> `\bfseries`), leaving any following text untouched, so it is correct by construction.
An obsolete two-letter font switch:
```tex
{\bf important}
```
```text
warning: deprecated-command
--> example.tex:1:2
|
1 | {\bf important}
| ^^^ `\bf` is deprecated; use `\bfseries`
```
After applying the fix:
```tex
{\bfseries important}
```