Powershell: Find and replace words split by newline - powershell

Question

So I have a text file that looks something like this:
Members : {USER\member1, USER\member2, US
ER\member3, USER\member4, USER
\member5, USER\member6}
and I would like to remove USER\. The following code removes it but not when it's split by a newline, for example when US on one line and ER\ on another line.
Foreach-Object { %{$_.Replace('USER\', '') }
Putting `n or `r in there doesn't work. Any help is appreciated.

Answer 1

Try this:
PS > ((Get-Content .\t.txt) | % { $_.Trim() }) -join "" -replace "USER\\"
Members : {member1, member2, member3, member4, member5, member6}
If the text is in a string-array, switch out (Get-Content .\t.txt) with your variable. If you have the text in a string(not array) variable, use:
($MYSTRINGVAR.Split("`r`n") | % { $_.Trim() }) -join "" -replace "USER\\"
EDIT Just modify the "Members" part:
$text = (Get-Content .\input.txt) -join "`r`n"
($text | Select-String '(?s)(?<=Members : \{)(.+?)(?=\})' -AllMatches).Matches | % {
$text = $text.Replace($_.Value, ($_.Value -split "`r`n" | % { $_.Trim() }) -join "" -replace "USER\\")
}
$text | Set-Content output.txt

Answer 2

There are probably easier ways to get there, but you can give this one a try:
$Text = #'
Members : {USER\member1, USER\member2, US
ER\member3, USER\member4, USER
\member5, USER\member6}
'#
# First - USER\ with newline inside..
foreach ($index in 1..4) {
$Text = $Text -replace ('USER\\'.Insert($index,'(\r\n\s+)')), '$1'
}
# Than - pure USER\
$Text = $Text -replace 'USER\\'
$Text
As you can see I create few patterns that contain and keep that element in results (, '$1'). For simple ones - I just remove USER\
I've used herestring to create text to work with, it's possible that \r may not be needed for actual file.

Answer 3

This is actually just a comment to Graimer's solution, but it would've been too long and also not readable enough as a comment, so I'm making it a (supplementary) answer instead.
To re-wrap the string after removing USER\ you could do something like this:
$s = "Members : {member1, member2, member3, member4, member5, member6}"
$s -match '^(.*?{)(.*)(})$'
$pad = " " * $matches[1].Length
$matches[1] + ($matches[2] -replace '(.{1,20},) ', "`$1`r`n$pad") + $matches[3]
The first regular expression splits the string into 3 parts that can be accessed via the $matches collection:
Name Value
---- -----
3 }
2 member1, member2, member3, member4, member5, member6
1 Members : {
0 Members : {member1, member2, member3, member4, member5, member6}
$matches[1] is the prologue including the opening curly bracket, $matches[2] is the member list, and $matches[3] is the closing curly bracket. Now you only need to wrap $matches[2] at whatever length you want:
'(.*{1,20},) '
The above means "longest match of at most 20 characters followed by a comma and a space". Replace that with the 1st group ($1) followed by a line-break (```rn``) and a number of spaces that matches the length of the prologue ($pad`) and glue it back together with prologue and trailing curly bracket.