In larger source trees, ct lshistory -r is dramatically less efficient than ct
lshistory -avob, when possible. While lshistory -r is more flexible than
lshistory -avob (since it can handle just a specific subdirectory within a VOB,
e.g.), it'd be great if the option to use -avobs was there. I'll look into this
and see what would be involved in adding this.