From c5829e9ffc7d5a6e32325881847aedb98eabed74 Mon Sep 17 00:00:00 2001
From: Matthew Holt <mholt@users.noreply.github.com>
Date: Sat, 14 Apr 2018 18:40:57 -0600
Subject: [PATCH 1/2] key: Add flag for non-interactive password changes

---
 cmd/restic/cmd_key.go | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/cmd/restic/cmd_key.go b/cmd/restic/cmd_key.go
index 7552c778d..d81be6bb9 100644
--- a/cmd/restic/cmd_key.go
+++ b/cmd/restic/cmd_key.go
@@ -3,6 +3,9 @@ package main
 import (
 	"context"
 	"fmt"
+	"io/ioutil"
+	"os"
+	"strings"
 
 	"github.com/restic/restic/internal/errors"
 	"github.com/restic/restic/internal/repository"
@@ -23,8 +26,13 @@ The "key" command manages keys (passwords) for accessing the repository.
 	},
 }
 
+var newPasswordFile string
+
 func init() {
 	cmdRoot.AddCommand(cmdKey)
+
+	flags := cmdKey.Flags()
+	flags.StringVarP(&newPasswordFile, "new-password-file", "", "", "the file from which to load a new password")
 }
 
 func listKeys(ctx context.Context, s *repository.Repository) error {
@@ -64,6 +72,10 @@ func getNewPassword(gopts GlobalOptions) (string, error) {
 		return testKeyNewPassword, nil
 	}
 
+	if newPasswordFile != "" {
+		return loadPasswordFromFile(newPasswordFile)
+	}
+
 	// Since we already have an open repository, temporary remove the password
 	// to prompt the user for the passwd.
 	newopts := gopts
@@ -182,3 +194,11 @@ func runKey(gopts GlobalOptions, args []string) error {
 
 	return nil
 }
+
+func loadPasswordFromFile(pwdFile string) (string, error) {
+	s, err := ioutil.ReadFile(pwdFile)
+	if os.IsNotExist(err) {
+		return "", errors.Fatalf("%s does not exist", pwdFile)
+	}
+	return strings.TrimSpace(string(s)), errors.Wrap(err, "Readfile")
+}

From 1a26355dbe742d740a99d7ccd3f51e773f3e7a26 Mon Sep 17 00:00:00 2001
From: Matthew Holt <mholt@users.noreply.github.com>
Date: Sat, 14 Apr 2018 18:49:33 -0600
Subject: [PATCH 2/2] Add changelog file

---
 changelog/unreleased/pull-1720 | 7 +++++++
 1 file changed, 7 insertions(+)
 create mode 100644 changelog/unreleased/pull-1720

diff --git a/changelog/unreleased/pull-1720 b/changelog/unreleased/pull-1720
new file mode 100644
index 000000000..90f23add4
--- /dev/null
+++ b/changelog/unreleased/pull-1720
@@ -0,0 +1,7 @@
+Enhancement: Add --new-password-file flag for non-interactive password changes
+
+This makes it possible to change a repository password without being prompted.
+
+https://github.com/restic/restic/issues/827
+https://github.com/restic/restic/pull/1720
+https://forum.restic.net/t/changing-repo-password-without-prompt/591