{"id":254,"date":"2014-12-03T00:01:00","date_gmt":"2014-12-03T00:01:00","guid":{"rendered":"https:\/\/blogs.technet.microsoft.com\/heyscriptingguy\/2014\/12\/03\/enforce-better-script-practices-by-using-set-strictmode\/"},"modified":"2019-02-18T10:36:47","modified_gmt":"2019-02-18T17:36:47","slug":"enforce-better-script-practices-by-using-set-strictmode","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/scripting\/enforce-better-script-practices-by-using-set-strictmode\/","title":{"rendered":"Enforce Better Script Practices by Using Set-StrictMode"},"content":{"rendered":"

Summary<\/b>: Boe Prox shows how to use <\/span>Set-StrictMode<\/b> to write better scripts.<\/span>\nHonorary Scripting Guy and Windows PowerShell MVP, Boe Prox, here today filling in for my good friend, The Scripting Guy. This is the third part in a series of five posts about troubleshooting Windows PowerShell scripts and functions. The series includes:<\/p>\n

    \n
  1. Provide Support by Using Verbose and Debug Streams<\/a><\/li>\n
  2. Troubleshoot by Using Set-PSDebug<\/a><\/li>\n
  3. Enforce Better Script Practices by Using Set-StrictMode<\/b> (this post)<\/li>\n
  4. Trace Your Commands by Using Trace-Command<\/li>\n
  5. Use the PowerShell Debugger<\/li>\n<\/ol>\n

    If you remember back in the VBScript days, if you wanted to enforce better practices with the handling of undeclared variables in your code, you would use Option Explicit<\/b>. If you tried to throw in a variable that wasn’t defined at the top of the script, it would throw an error message and stop executing. Well, we’ve come further along with Windows PowerShell.\nBy using the Set-StrictMode<\/b> cmdlet, we can enforce some common “best practice” coding techniques that you can use with your scripts. In yesterday’s post, I used the –Strict<\/b> parameter with Set-PSDebug<\/b>. This enforces the variable declaration in a script. But with Set-StrictMode<\/b>, we get that plus a little more. The scope is limited to the current scope and child scopes. By default, Set-StrictMode<\/b> is turned off to prevent error messages while you are writing the script.\nYou only have two parameters to deal with: -Off<\/b> and -Version<\/b>.<\/p>\n\n\n\n\n
     Off<\/b><\/p>\n<\/td>\n\n

     Turns off StrictMode<\/b>.<\/p>\n<\/td>\n<\/tr>\n

    \n

     Version<\/b><\/p>\n<\/td>\n

    		\n

     There are three possible values that can be supplied with this parameter:<\/p>\n

     -Version 1.0<\/b>
     Prevents use of variables that have not been initialized (think Option Explicit<\/b> in VBScript)<\/b><\/p>\n

     -Version 2.0<\/b><\/p>\n