You can search for, or make replacements with, Environment Variables . Searches may be case sensitive or not and can use a Regular Expression strings.
The syntax is:
where variable name is the name of the environment variable to use.
For example, to search a string held in the environment variable temp, uses this search string:
If the value of your temp environment variable is C:\Users\tom\AppData\Local\Temp , search hits will occur wherever the string C:\Users\tom\AppData\Local\Temp is found in the files being searched. If Case Sensitive is on, C:\Users\tom\AppData\Local\Temp would be found but C:\USERS\TOM\APPDATA\LOCAL\TEMP would not.
To use the value of the environment variable SystemRoot in a replacement string, enter the string
in replacement text field. If the value of SystemRoot for your computer is variable is C:\WINDOWS, the string C:\WINDOWS would be used in replacements.
A regular expression operation involving the environment variables operators might be: