Using -replace on pipes in powershell

Question

I want to test out a replace before I use it, so I'm trying to write a quick online command to see what the output is. However, I'm not sure what the syntax is. What I want to do is something like

cat file | -replace "a", "b"

What is the correct powershell syntax for this?

I know that I can also do $a = cat file and then do a replace on $a, but I'de like to keep this on one line

Answer 1

This should do the trick, it'll go through all the lines in the file, and replace any "a" with "b", but you'll need to save that back into a file afterwards

cat file | % {$_.replace("a","b")} | out-file newfile

Answer 2

To use the Powershell -replace operator (which works with regular expressions) do this:

cat file.txt | % {$_ -replace "\W", ""} # -replace operator uses regex

note that the -replace operator uses regex matching, whereas the following example would use a non-regex text find and replace, as it uses the String.Replace method of the .NET Framework

cat file | % {$_.replace("abc","def")} # string.Replace uses text matching