diff --git a/pkg/exprenv/exprenv.go b/pkg/exprenv/exprenv.go
index 97fb49f..7bd574b 100644
--- a/pkg/exprenv/exprenv.go
+++ b/pkg/exprenv/exprenv.go
@@ -61,6 +61,7 @@ func BaseFuncs(ptyEnabled bool) map[string]any {
 		"truncate":              exprfuncs.Truncate,
 		"substr":                exprfuncs.Substr,
 		"formatOrder":           exprfuncs.FormatOrder,
+		"env":                   exprfuncs.Env,
 	}
 }
 
diff --git a/pkg/exprenv/exprfuncs/exprfuncs.go b/pkg/exprenv/exprfuncs/exprfuncs.go
index eca2282..c3031a7 100644
--- a/pkg/exprenv/exprfuncs/exprfuncs.go
+++ b/pkg/exprenv/exprfuncs/exprfuncs.go
@@ -8,6 +8,7 @@ package exprfuncs
 import (
 	"encoding/json"
 	"fmt"
+	"os"
 	"strconv"
 	"strings"
 	"time"
@@ -414,3 +415,15 @@ func IsBlank(v any) bool {
 	s, ok := v.(string)
 	return ok && s == ""
 }
+
+// Env returns the value of the named environment variable, or def (default "")
+// when it is unset or empty.
+func Env(name string, def ...string) string {
+	if v := os.Getenv(name); v != "" {
+		return v
+	}
+	if len(def) > 0 {
+		return def[0]
+	}
+	return ""
+}