CosmOS
> loaded, starting at 4000
> poem.txt, 0 lines
> : : : : > : : > 1: alpha
2: INSERTED
3: beta
4: gamma
> : > > 1: CHANGED
2: INSERTED
3: beta
> written, 22 bytes
> finished
> poem.txt, 3 lines
> 1: CHANGED
2: INSERTED
3: beta
> there is no such line
> finished
> halted
Execution halted.
[exit 0]