safety Archives - More Zonkyness

20mph Speed Limit and Prioritising Vulnerable Road Users Considered Harmful

Feb 132023

(‘bad’ language ahead)

Bollocks.

Reducing the speed limit from 30mph to 20mph reduces the fatality of hitting a pedestrian or cyclist from 40% to 5%. Slower speeds are fundamentally safer on crowded urban roads, and small country lanes – everyone has more time to react and even in the worst case where a collision occurs, the accident is more survivable.

There are those who claim the lower speeds will slow them down – tough! That continually looking at the speedometer is more dangerous – get used to lower speeds. All of the excuses I have seen amount to selfishness.

And similarly the opposition to prioritising vulnerable road users – letting pedestrians cross at junctions, giving cyclists at least 1.5m of space when overtaking, etc. all amount to motorists’ entitlement. You aren’t more important, you don’t pay for the roads, and the safety of cyclists and pedestrians takes priority to your convenience.

Shell Alias May Be Dangerous

Computing, Linux No Responses »

Jul 132022

Not all shell aliases of course, but some. I’ve just seen a youtube video that suggested creating a shell alias to run rmtrash when rm is invoked :-

alias rm='rmtrash'

Seems sensible enough doesn’t it? This is in fact the classic example of how dangerous shell aliases can be, although the classic example was to turn on “-i” :-

alias rm='rm -i'

The problem is that you get used to “rm” being safe – either it asks before it removes files (“-i”) or it safely preserves what is deleted in the Trash folder. But what happens when the alias doesn’t get created? Perhaps you have a broken .zshrc and Zsh stops interpreting before the alias is declared. Or you’ve logged on to a remote server that doesn’t have your .zshrc installed as yet?

All of a sudden you are running the unadulterated rm command – deleting files without being asked, or preserving them in the Trash folder. See the danger now?

It is better not to replace standard commands but create a new ‘command’ :-

alias del="rmtrash"

Perhaps you regard this as being excessively risk averse – fair enough. But just don’t say you weren’t warned – and I’ve encountered missing aliases every year over the last 30-odd years I’ve been using Linux and Unix.