Snippet to search and replace in file via regex certain patterns.

SearchAndReplaceRegEx.ps1

# Already case-insensitive.  Use -cmatch and -creplace for case-sensitive matching and replacement.
(Get-Content input.json) `
  -replace '\d{15,19}', {'*' * ($_.Value.Length-4) + $_.Value.Substring($_.Value.Length - 5, 4)} `
  -replace '(\"expirationMonth\":)(\s*)("\d{1,2}")', '$1$2"**"' `
  -replace '(\"expirationYear\":)(\s*)("\d{2,4}")', '$1$2"****"' `
  -replace '(\"cvn\":)(\s*)("\d{3,4}")', '$1$2"***"' |
 Out-File output.json

# Where $1 is the first group for example "CVN": and $2 is the second group (zero or more spaces) and $3 is the value.

# Alternatively if we wanted to masking with groups
# -replace '(\"cvn\":)\s+"(\d{2})(\d{1,2})"', '$1 **$3'