diff --git a/cat/cat.go b/cat/cat.go
index d56265d..17d9823 100644
--- a/cat/cat.go
+++ b/cat/cat.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"log"
 	"os"
+	"path/filepath"
 	"strings"
 
 	"github.com/brtholomy/um/go/cmd"
@@ -19,19 +20,22 @@ const (
 
 type options struct {
 	Filelist flags.Arg
+	Base     flags.Flag[string]
 	Help     flags.Flag[bool]
 }
 
 func initOpts() options {
 	return options{
 		flags.Arg{"", "filelist. accepts from stdin if not provided"},
+		flags.Flag[string]{"--base", "-b", "", "base directory prepended to files in filelist"},
 		flags.Flag[bool]{"--help", "-h", false, "show help"},
 	}
 }
 
-func cat(files []string) (string, error) {
+func cat(files []string, base string) (string, error) {
 	ff := make([]string, 0, len(files))
 	for _, f := range files {
+		f := filepath.Join(base, f)
 		dat, err := os.ReadFile(f)
 		if err != nil {
 			return "", fmt.Errorf("error opening target file: %w", err)
@@ -48,7 +52,7 @@ func Cat(args []string) {
 	if err != nil {
 		log.Fatalf("um %s: %s", CMD, err)
 	}
-	s, err := cat(files)
+	s, err := cat(files, opts.Base.Val)
 	if err != nil {
 		log.Fatalf("um %s: %s", CMD, err)
 	}