firefox proxy settings via command line

Question

How do I change Firefox Proxy settings via command line on windows xp/2k?

Thanks

Answer 1

I found a better way to do this with powershell under windows (but really only because I was looking for a way to script changing the user agent string, not muck about with proxies).

function set-uas
{
    Param
    (
            [string]$UAS = "Default"
    )

    $FirefoxPrefs = "C:\Users\Admin\AppData\Roaming\Mozilla\Firefox\Profiles\*.default\prefs.js"

    if ($UAS -eq "Default")
    {
        $fileinfo = type $FirefoxPrefs
        $fileinfo = $fileinfo | findstr /v "general.appname.override"    
        $fileinfo = $fileinfo | findstr /v "general.appversion.override"
        $fileinfo = $fileinfo | findstr /v "general.platform.override"  
        $fileinfo = $fileinfo | findstr /v "general.useragent.appName"  
        $fileinfo = $fileinfo | findstr /v "general.useragent.override" 
        $fileinfo = $fileinfo | findstr /v "general.useragent.vendor"   
        $fileinfo = $fileinfo | findstr /v "general.useragent.vendorSub"
        $fileinfo += "user_pref(`"useragentswitcher.import.overwrite`", false);`n"
        $fileinfo += "user_pref(`"useragentswitcher.menu.hide`", false);`n"
        $fileinfo += "user_pref(`"useragentswitcher.reset.onclose`", false);`n"
        $fileinfo | Out-File -FilePath $FirefoxPrefs -Encoding ASCII
    }
    else
    {
        set-uas Default
    }

    if ($UAS -eq "iphone")
    {
        $fileinfo = ""
        $fileinfo += "user_pref(`"general.appname.override`", `"Netscape`");`n"
        $fileinfo += "user_pref(`"general.appversion.override`", `"5.0 (iPhone; U; CPU iPhone OS 3_0 like Mac OS X; en-us) AppleWebKit/528.18 (KHTML, like Gecko) Version/4.0 Mobile/7A341 Safari/528.16`");`n"
        $fileinfo += "user_pref(`"general.platform.override`", `"iPhone`");`n"                                                                                                                                      
        $fileinfo += "user_pref(`"general.useragent.appName`", `"Mozilla`");`n"                                                                                                                                     
        $fileinfo += "user_pref(`"general.useragent.override`", `"Mozilla/5.0 (iPhone; U; CPU iPhone OS 3_0 like Mac OS X; en-us) AppleWebKit/528.18 (KHTML, like Gecko) Version/4.0 Mobile/7A341 Safari/528.16`");`n"
        $fileinfo += "user_pref(`"general.useragent.vendor`", `"Apple Computer, Inc.`");`n"                                                                                                                         
        $fileinfo += "user_pref(`"general.useragent.vendorSub`", `"`");`n"                                                                                                                                          
        $fileinfo += "user_pref(`"useragentswitcher.reset.onclose`", false);`n"
        $fileinfo | Out-File -FilePath $FirefoxPrefs -Encoding ASCII -Append
    }
    elseif ($UAS -eq "lumia")
    {
        $fileinfo = ""
        $fileinfo += "user_pref(`"general.appname.override`", `"Netscape`");`n"
        $fileinfo += "user_pref(`"general.appversion.override`", `"9.80 (Windows Phone; Opera Mini/9.0.0/37.6652; U; en) Presto/2.12.423 Version/12.16`");`n"
        $fileinfo += "user_pref(`"general.platform.override`", `"Nokia`");`n"                                                                                                                                       
        $fileinfo += "user_pref(`"general.useragent.appName`", `"Mozilla`");`n"                                                                                                                                     
        $fileinfo += "user_pref(`"general.useragent.override`", `"Opera/9.80 (Windows Phone; Opera Mini/9.0.0/37.6652; U; en) Presto/2.12.423 Version/12.16`");`n"
        $fileinfo += "user_pref(`"general.useragent.vendor`", `"Microsoft`");`n"                                                                                                                            
        $fileinfo += "user_pref(`"general.useragent.vendorSub`", `"`");`n"                                                                                                                                          
        $fileinfo += "user_pref(`"useragentswitcher.reset.onclose`", false);`n"
        $fileinfo | Out-File -FilePath $FirefoxPrefs -Encoding ASCII -Append
    }
}

I have the firefox plugin "useragentswitcher" also installed, and have not tested this without it.
I also have set "user_pref("useragentswitcher.reset.onclose", false);"

[EDIT] I've revised my code, it was occasionally outputting some bad character or something. For some reason this is detected by firefox as a corrupt profile, and the entire profile was discarded, and refreshed with a default profile.

Also, credit where credit is due: this code is loosely based off of what xBoarder posted in his response to sam3344920 (https://stackoverflow.com/a/2509088/5403057). Also, I was able to fix the encoding bug with help from a post from Phoenix14830 (https://stackoverflow.com/a/32080395/5403057)

[Edit2] Added support for setting the UAS to lumia. This is actually using an Opera mobile UAS, because I still wanted bing to work, and if you use the regular lumia UAS www.bing.com redirects to bing://?%^&* which firefox doesn't know how to process