Split string with PowerShell and do something with each token
I want to split each line of a pipe on spaces, and then print each token on its own line.
I realise that I can get this result using:
(cat someFileInsteadOfAPipe).split(" ")
But I want more flexibility. I want to be able to do just about anything with each token. (I used to use AWK on Unix, and I'm trying to get the same functionality.)
I currently have:
echo "Once upon a time there were three little pigs" | %{$data = $_.split(" "); Write-Output "$($data[0]) and whatever I want to output with it"}
Which, obviously, only prints the first token. Is there a way for me to for-each over the tokens, printing each in turn?
Also, the %{$data = $_.split(" "); Write-Output "$($data[0])"} part I got from a blog, and I really don't understand what I'm doing or how the syntax works.
I want to google for it, but I don't know what to call it. Please help me out with a word or two to Google, or a link explaining to me what the % and all the $ symbols do, as well as the significance of the opening and closing brackets.
I realise I can't actually use (cat someFileInsteadOfAPipe).split(" "), since the file (or preferable incoming pipe) contains more than one line.
Regarding some of the answers:
If you are using Select-String to filter the output before tokenizing, you need to keep in mind that the output of the Select-String command is not a collection of strings, but a collection of MatchInfo objects. To get to the string you want to split, you need to access the Line property of the MatchInfo object, like so:
cat someFile | Select-String "keywordFoo" | %{$_.Line.Split(" ")}
Answer
"Once upon a time there were three little pigs".Split(" ") | ForEach {
"$_ is a token"
}
The key is $_, which stands for the current variable in the pipeline.
About the code you found online:
% is an alias for ForEach-Object. Anything enclosed inside the brackets is run once for each object it receives. In this case, it's only running once, because you're sending it a single string.
$_.Split(" ") is taking the current variable and splitting it on spaces. The current variable will be whatever is currently being looped over by ForEach.