ForEach vs ForEach vs ForEach

Here’s all three in action, in a very simplistic example:

The big difference is that, in the pipeline, ForEach-Object _processes one object at a time. _That means it can be slower, since that scriptblock must be interpreted on each iteration. It also tends to use less memory, since objects streaming down the pipeline one at a time don’t all have to be bunched up in a variable first.

Both use vaguely similar syntax, but there are differences. It’s important to understand that they are not the same, and that they execute differently. It’s confusing because “ForEach” is both an alias and a scripting construct; the shell determines which you’re using by looking at the context in which you’re using it.