How to test if a windows group exists from inno setup? - inno-setup

Question

How can you test to see if a windows group is already setup? Can you somehow use the response from:
Exec('net.exe', 'localgroup', '', SW_SHOW, ewWaitUntilTerminated, Result);
which will list the groups to the command prompt? (I know that Result is an error code where 0 is success, just to be clear.)
Is there a way? Is there more than one way?

Answer 1

I haven't tested this, or had time to work out the exact process or syntax, but you could possibly use command redirection (see https://technet.microsoft.com/en-us/library/bb490982.aspx), using net localgroup as you suggested, to find the group name and output it to a text file. You could then read it into Inno Setup using LoadStringFromFile, then all you would need to do is compare the two strings.
So, having looked at this in more detail, to see if the Administrators group exists you could use:
[Run]
Filename: "{cmd}"; Parameters: "/c ""net localgroup | find /i ""Administrators"" > ""{tmp}\groupresult.txt"""""; StatusMsg: "Querying user groups..."; Flags: runhidden
[Code]
var
strGroupResult: String;
begin
LoadStringFromFile(ExpandConstant('{tmp}\groupresult.txt'), strGroupResult);
if strGroupResult = '*Administrators' then
begin
//Code to execute if group exists
...
end;
DeleteFile(ExpandConstant('{tmp}\groupresult.txt'));
end;
Note that net localgroup returns an asterisk (*) in front of the group name, so the string comparison needs to also include the asterisk.
If you need to do this before the [Run] section, you can write a similar Exec line in the [Code] section to run the same process.