From 9.2 Bash History Builtin:
> If @var{last} is not specified it is set to @var{first}
Missing comma after the dependent clause. It should read:
If @var{last} is not specified, it is set to @var{first}
Grammar references:
* https://www.ego4u.com/en/cram-up/writing/comma?10
* https://www.grammarly.com/blog/conditional-sentences/
*
https://english.stackexchange.com/questions/6786/comma-in-conditional-sentence-and-in-antithesis
