diff --git a/compiler/commands.nim b/compiler/commands.nim
index ca6ef5d94588..d367823414c6 100644
--- a/compiler/commands.nim
+++ b/compiler/commands.nim
@@ -309,7 +309,7 @@ proc testCompileOption*(conf: ConfigRef; switch: string, info: TLineInfo): bool
 
 proc processPath(conf: ConfigRef; path: string, info: TLineInfo,
                  notRelativeToProj = false): AbsoluteDir =
-  let p = if os.isAbsolute(path) or '$' in path:
+  let p = if os.isAbsolute(path) or path.shouldPathSubs:
             path
           elif notRelativeToProj:
             getCurrentDir() / path
@@ -325,7 +325,7 @@ proc processCfgPath(conf: ConfigRef; path: string, info: TLineInfo): AbsoluteDir
   let path = if path.len > 0 and path[0] == '"': strutils.unescape(path)
              else: path
   let basedir = toFullPath(conf, info).splitFile().dir
-  let p = if os.isAbsolute(path) or '$' in path:
+  let p = if os.isAbsolute(path) or path.shouldPathSubs:
             path
           else:
             basedir / path
diff --git a/compiler/options.nim b/compiler/options.nim
index c39ffa792b0f..781a4464e9b4 100644
--- a/compiler/options.nim
+++ b/compiler/options.nim
@@ -590,9 +590,15 @@ proc getNimcacheDir*(conf: ConfigRef): AbsoluteDir =
             AbsoluteDir(getOsCacheDir() / splitFile(conf.projectName).name &
                (if isDefined(conf, "release") or isDefined(conf, "danger"): "_r" else: "_d"))
 
+const subs = {'$', '@'}
+
+proc shouldPathSubs*(input: string): bool =
+  input.contains(subs + {'~'})
+
 proc pathSubs*(conf: ConfigRef; p, config: string): string =
   let home = removeTrailingDirSep(os.getHomeDir())
-  result = unixToNativePath(p % [
+  result = ""
+  result.addfCustom(p, subs = subs, [
     "nim", getPrefixDir(conf).string,
     "lib", conf.libpath.string,
     "home", home,
@@ -600,14 +606,17 @@ proc pathSubs*(conf: ConfigRef; p, config: string): string =
     "projectname", conf.projectName,
     "projectpath", conf.projectPath.string,
     "projectdir", conf.projectPath.string,
-    "nimcache", getNimcacheDir(conf).string]).expandTilde
+    "nimcache", getNimcacheDir(conf).string])
+  result = unixToNativePath(result).expandTilde
 
 iterator nimbleSubs*(conf: ConfigRef; p: string): string =
   let pl = p.toLowerAscii
-  if "$nimblepath" in pl or "$nimbledir" in pl:
+  if "$nimblepath" in pl or "$nimbledir" in pl or "@nimblepath" in pl or "@nimbledir" in pl:
     for i in countdown(conf.nimblePaths.len-1, 0):
       let nimblePath = removeTrailingDirSep(conf.nimblePaths[i].string)
-      yield p % ["nimblepath", nimblePath, "nimbledir", nimblePath]
+      var ret = ""
+      ret.addfCustom(p, subs = subs, ["nimblepath", nimblePath, "nimbledir", nimblePath])
+      yield ret
   else:
     yield p
 
diff --git a/compiler/scriptconfig.nim b/compiler/scriptconfig.nim
index e9e720b1b71b..7171c65e3f39 100644
--- a/compiler/scriptconfig.nim
+++ b/compiler/scriptconfig.nim
@@ -175,7 +175,7 @@ proc setupVM*(module: PSym; cache: IdentCache; scriptName: string;
   cbconf patchFile:
     let key = a.getString(0) & "_" & a.getString(1)
     var val = a.getString(2).addFileExt(NimExt)
-    if {'$', '~'} in val:
+    if val.shouldPathSubs:
       val = pathSubs(conf, val, vthisDir)
     elif not isAbsolute(val):
       val = vthisDir / val
diff --git a/lib/pure/strutils.nim b/lib/pure/strutils.nim
index 535af2b318c6..4f4da14b1391 100644
--- a/lib/pure/strutils.nim
+++ b/lib/pure/strutils.nim
@@ -2623,69 +2623,80 @@ proc findNormalized(x: string, inArray: openArray[string]): int =
 proc invalidFormatString() {.noinline.} =
   raise newException(ValueError, "invalid format string")
 
-proc addf*(s: var string, formatstr: string, a: varargs[string, `$`]) {.
-  noSideEffect, rtl, extern: "nsuAddf".} =
+proc addfCustom*(s: var string, formatstr: string, subs = {'$'}, a: varargs[string, `$`]) {.
+  noSideEffect, rtl, extern: "nsuAddf2".} =
   ## The same as ``add(s, formatstr % a)``, but more efficient.
+  runnableExamples:
+    var s = "start:"
+    s.addfCustom("$foo @bar $$ @@ $", subs = {'$', '@'}, ["foo", "FOO", "bar", "BAR"])
+    doAssert s == "start:FOO BAR $ @ $"
+
   const PatternChars = {'a'..'z', 'A'..'Z', '0'..'9', '\128'..'\255', '_'}
   var i = 0
   var num = 0
   while i < len(formatstr):
-    if formatstr[i] == '$' and i+1 < len(formatstr):
-      case formatstr[i+1]
-      of '#':
-        if num > a.high: invalidFormatString()
-        add s, a[num]
-        inc i, 2
-        inc num
-      of '$':
-        add s, '$'
+    if formatstr[i] in subs and i+1 < len(formatstr):
+      if formatstr[i+1] == formatstr[i]:
+        add s, formatstr[i]
         inc(i, 2)
-      of '1'..'9', '-':
-        var j = 0
-        inc(i) # skip $
-        var negative = formatstr[i] == '-'
-        if negative: inc i
-        while i < formatstr.len and formatstr[i] in Digits:
-          j = j * 10 + ord(formatstr[i]) - ord('0')
-          inc(i)
-        let idx = if not negative: j-1 else: a.len-j
-        if idx < 0 or idx > a.high: invalidFormatString()
-        add s, a[idx]
-      of '{':
-        var j = i+2
-        var k = 0
-        var negative = formatstr[j] == '-'
-        if negative: inc j
-        var isNumber = 0
-        while j < formatstr.len and formatstr[j] notin {'\0', '}'}:
-          if formatstr[j] in Digits:
-            k = k * 10 + ord(formatstr[j]) - ord('0')
-            if isNumber == 0: isNumber = 1
-          else:
-            isNumber = -1
-          inc(j)
-        if isNumber == 1:
-          let idx = if not negative: k-1 else: a.len-k
+      else:
+        case formatstr[i+1]
+        of '#':
+          if num > a.high: invalidFormatString()
+          add s, a[num]
+          inc i, 2
+          inc num
+        of '1'..'9', '-':
+          var j = 0
+          inc(i) # skip subs
+          var negative = formatstr[i] == '-'
+          if negative: inc i
+          while i < formatstr.len and formatstr[i] in Digits:
+            j = j * 10 + ord(formatstr[i]) - ord('0')
+            inc(i)
+          let idx = if not negative: j-1 else: a.len-j
           if idx < 0 or idx > a.high: invalidFormatString()
           add s, a[idx]
-        else:
-          var x = findNormalized(substr(formatstr, i+2, j-1), a)
+        of '{':
+          var j = i+2
+          var k = 0
+          var negative = formatstr[j] == '-'
+          if negative: inc j
+          var isNumber = 0
+          while j < formatstr.len and formatstr[j] notin {'\0', '}'}:
+            if formatstr[j] in Digits:
+              k = k * 10 + ord(formatstr[j]) - ord('0')
+              if isNumber == 0: isNumber = 1
+            else:
+              isNumber = -1
+            inc(j)
+          if isNumber == 1:
+            let idx = if not negative: k-1 else: a.len-k
+            if idx < 0 or idx > a.high: invalidFormatString()
+            add s, a[idx]
+          else:
+            var x = findNormalized(substr(formatstr, i+2, j-1), a)
+            if x >= 0 and x < high(a): add s, a[x+1]
+            else: invalidFormatString()
+          i = j+1
+        of 'a'..'z', 'A'..'Z', '\128'..'\255', '_':
+          var j = i+1
+          while j < formatstr.len and formatstr[j] in PatternChars: inc(j)
+          var x = findNormalized(substr(formatstr, i+1, j-1), a)
           if x >= 0 and x < high(a): add s, a[x+1]
           else: invalidFormatString()
-        i = j+1
-      of 'a'..'z', 'A'..'Z', '\128'..'\255', '_':
-        var j = i+1
-        while j < formatstr.len and formatstr[j] in PatternChars: inc(j)
-        var x = findNormalized(substr(formatstr, i+1, j-1), a)
-        if x >= 0 and x < high(a): add s, a[x+1]
-        else: invalidFormatString()
-        i = j
-      else:
-        invalidFormatString()
+          i = j
+        else:
+          invalidFormatString()
     else:
       add s, formatstr[i]
       inc(i)
 
+proc addf*(s: var string, formatstr: string, a: varargs[string, `$`]) {.
+  noSideEffect, rtl, extern: "nsuAddf".} =
+  ## Wrapper around `addfCustom` with subs = {'$'}
+  addfCustom(s, formatstr, subs = {'$'}, a)
+
 proc `%` *(formatstr: string, a: openArray[string]): string {.noSideEffect,
   rtl, extern: "nsuFormatOpenArray".} =
   ## Interpolates a format string with the values from `a`.