Funkcionalnosć toś togo sedła se pśez wótwardowańske źěła wobgranicujo, kótarež maju wašo dožywjenje pólěpšyś. Jolic nastawk waš problem njerozwězujo a cośo pšašanje stajiś, wobrośćo se na našo zgromoźeństwo pomocy, kótarež na to caka, wam na @FirefoxSupport na Twitter a /r/firefox na Reddit pomagaś.

Pomoc pśepytaś

Glědajśo se wobšudy pomocy. Njenapominajomy was nigda, telefonowy numer zawołaś, SMS pósłaś abo wósobinske informacije pśeraźiś. Pšosym dajśo suspektnu aktiwitu z pomocu nastajenja „Znjewužywanje k wěsći daś“ k wěsći.

Dalšne informacije

What is the Firefox equivalent of Windows' %username%?

  • 4 wótegrona
  • 1 ma toś ten problem
  • 3 naglědy
  • Slědne wótegrono wót cor-el

more options

I'm trying to setup username variables in about:config, notably default download location and browser.cache.disk.parent_directory . When I use the standard %username% variable in these settings, Firefox interprets them literally. Does Firefox have an equivalent %username% variable?

This happened

Every time Firefox opened

== Always

I'm trying to setup username variables in about:config, notably default download location and browser.cache.disk.parent_directory . When I use the standard %username% variable in these settings, Firefox interprets them literally. Does Firefox have an equivalent %username% variable? == This happened == Every time Firefox opened == Always

Wšykne wótegrona (4)

more options

No. You do not have access to environment variables on the about:config page.

You can get that value via the Tools > Error Console if necessary. Copy and Paste this code in the Code field and click evaluate.

Components.classes["@mozilla.org/process/environment;1"].getService(Components.interfaces.nsIEnvironment).get('USERNAME');

Wót cor-el změnjony

more options

With that code snippet, can the response be injected into the browser.cache.disk.parent_directory setting?

more options

An extension should be able to do that quite easily.
Try this code in the Tools Error Console.
You can create an extension to make the change.

const Cc = Components.classes, Ci = Components.interfaces;
var PB = Cc["@mozilla.org/preferences-service;1"].getService(Ci.nsIPrefService).getBranch("");
var PN = "browser.cache.disk.parent_directory";
var curVal = PB.getCharPref(PN);
var userName = Cc["@mozilla.org/process/environment;1"].getService(Ci.nsIEnvironment).get('USERNAME');
newVal = curVal.replace(/%USERNAME%/i, userName);
PB.setCharPref(PN, newVal);

See also:

Wót cor-el změnjony

more options

By "create an extension", do you mean just paste that code into a XPI?