diff --git a/doc.go b/doc.go
index 1704fcb3..300c6891 100644
--- a/doc.go
+++ b/doc.go
@@ -157,6 +157,7 @@ The following options can be used to customize the behavior of lf:
     waitmsg        string    (default 'Press any key to continue')
     wrapscan       bool      (default on)
     wrapscroll     bool      (default off)
+    user_{key}     string    (default none)
 
 The following environment variables are exported for shell commands:
 
@@ -172,6 +173,7 @@ The following environment variables are exported for shell commands:
     PAGER
     SHELL
     lf_{option}
+    lf_user_{key}
 
 The following special shell commands are used to customize the behavior of lf when defined:
 
@@ -795,6 +797,10 @@ Searching can wrap around the file list.
 
 Scrolling can wrap around the file list.
 
+    user_{key}     string    (default none)
+
+Any option that is prefixed with 'user_' is a user defined option and can be set to any string. Inside a user defined command the value will be provided in the `lf_user_{key}` environment variable. These options are not used by lf and are not persisted.
+
 Environment Variables
 
 The following variables are exported for shell commands:
diff --git a/docstring.go b/docstring.go
index c5c538b8..6d580a05 100644
--- a/docstring.go
+++ b/docstring.go
@@ -161,6 +161,7 @@ The following options can be used to customize the behavior of lf:
     waitmsg        string    (default 'Press any key to continue')
     wrapscan       bool      (default on)
     wrapscroll     bool      (default off)
+    user_{key}     string    (default none)
 
 The following environment variables are exported for shell commands:
 
@@ -176,6 +177,7 @@ The following environment variables are exported for shell commands:
     PAGER
     SHELL
     lf_{option}
+    lf_user_{key}
 
 The following special shell commands are used to customize the behavior of
 lf when defined:
@@ -848,6 +850,13 @@ Searching can wrap around the file list.
 
 Scrolling can wrap around the file list.
 
+    user_{key}     string    (default none)
+
+Any option that is prefixed with 'user_' is a user defined option and can be
+set to any string. Inside a user defined command the value will be provided
+in the 'lf_user_{key}' environment variable. These options are not used by
+lf and are not persisted.
+
 
 Environment Variables
 
diff --git a/eval.go b/eval.go
index 53191b46..a47d5ad9 100644
--- a/eval.go
+++ b/eval.go
@@ -432,7 +432,12 @@ func (e *setExpr) eval(app *app, args []string) {
 
 		gOpts.truncatechar = e.val
 	default:
-		app.ui.echoerrf("unknown option: %s", e.opt)
+		// any key with the prefix user_ is accepted as a user defined option
+		if strings.HasPrefix(e.opt, "user_") {
+			gOpts.user[e.opt[5:]] = e.val
+		} else {
+			app.ui.echoerrf("unknown option: %s", e.opt)
+		}
 		return
 	}
 	app.ui.loadFileInfo(app.nav)
diff --git a/lf.1 b/lf.1
index f0a7311c..5dc7dc37 100644
--- a/lf.1
+++ b/lf.1
@@ -176,6 +176,7 @@ The following options can be used to customize the behavior of lf:
     waitmsg        string    (default 'Press any key to continue')
     wrapscan       bool      (default on)
     wrapscroll     bool      (default off)
+    user_{key}     string    (default none)
 .EE
 .PP
 The following environment variables are exported for shell commands:
@@ -193,6 +194,7 @@ The following environment variables are exported for shell commands:
     PAGER
     SHELL
     lf_{option}
+    lf_user_{key}
 .EE
 .PP
 The following special shell commands are used to customize the behavior of lf when defined:
@@ -969,6 +971,12 @@ Searching can wrap around the file list.
 .EE
 .PP
 Scrolling can wrap around the file list.
+.PP
+.EX
+    user_{key}     string    (default none)
+.EE
+.PP
+Any option that is prefixed with 'user_' is a user defined option and can be set to any string. Inside a user defined command the value will be provided in the `lf_user_{key}` environment variable. These options are not used by lf and are not persisted.
 .SH ENVIRONMENT VARIABLES
 The following variables are exported for shell commands: These are referred with a '$' prefix on POSIX shells (e.g. '$f'), between '%' characters on Windows cmd (e.g. '%f%'), and with a '$env:' prefix on Windows powershell (e.g. '$env:f').
 .PP
diff --git a/main.go b/main.go
index 99a87a94..301e8b4f 100644
--- a/main.go
+++ b/main.go
@@ -152,6 +152,11 @@ func exportOpts() {
 
 			dirfirst := strconv.FormatBool(gOpts.sortType.option&dirfirstSort != 0)
 			os.Setenv("lf_dirfirst", dirfirst)
+		} else if name == "lf_user" {
+			// set each user option
+			for key, value := range gOpts.user {
+				os.Setenv(name+"_"+key, value)
+			}
 		} else {
 			field := e.Field(i)
 			value := fieldToString(field)
diff --git a/opts.go b/opts.go
index 2909809f..d0d700dd 100644
--- a/opts.go
+++ b/opts.go
@@ -72,6 +72,7 @@ var gOpts struct {
 	keys           map[string]expr
 	cmdkeys        map[string]expr
 	cmds           map[string]expr
+	user           map[string]string
 	sortType       sortType
 	tempmarks      string
 	tagfmt         string
@@ -231,6 +232,7 @@ func init() {
 	gOpts.cmdkeys["<a-t>"] = &callExpr{"cmd-transpose-word", nil, 1}
 
 	gOpts.cmds = make(map[string]expr)
+	gOpts.user = make(map[string]string)
 
 	setDefaults()
 }