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copied!<p>You are correct that a FOR /L loop "always" counts to completion. (Well, actually there are some drastic coding methods that can break it, but no need to go there)</p> <p>However, even though the loop counts to completion, the DO clause is skipped once the GOTO FOUND statement has been executed. You can prove this to yourself by inserting <code>echo testing %%a&</code> in the front of your existing DO clause. You will see that no additional testing takes place once you have found your free port.</p> <p>The FOR /L loop counts very fast (at least by batch standards), so I wouldn't worry about the extra counting. Now if your were counting 1 through 1 million, then I <em>might</em> worry. At 10 million I am definitely concerned.</p> <p>I can simplify your existing logic a bit. You can combine the 2 FIND statements into a single FINDSTR using a regular expression.</p> <pre><code>for /L %%a in (8000,1,8100) do netstat /a /n | findstr /rc:"%%a.*LISTENING" || set tmp_freeport=%%a && goto found </code></pre> <p>I am no expert concerning IP addresses and ports, but I am concerned that your FIND logic may be inadequate to screen for used ports. I think looking for a colon before and a space after the port will make it more reliable. Also, I doubt you want to see the text of the used ports, so I redirected the FINDSTR output to nul.</p> <pre><code>for /L %%a in (8000,1,8100) do netstat /a /n | findstr /rc:":%%a .*LISTENING" >nul || set tmp_freeport=%%a && goto found </code></pre> <p><em><strong>Note:</em></strong> GOTO :Label will immediately terminate all other forms of a FOR loop. Only the FOR /L variant continues to count after a GOTO.</p>

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