diff --git a/cmd/backup/config_provider.go b/cmd/backup/config_provider.go
index 0d33b185..62da12be 100644
--- a/cmd/backup/config_provider.go
+++ b/cmd/backup/config_provider.go
@@ -4,14 +4,14 @@
 package main
 
 import (
-	"bufio"
+	"context"
 	"fmt"
 	"os"
 	"path/filepath"
 
-	"github.com/joho/godotenv"
 	"github.com/offen/docker-volume-backup/internal/errwrap"
 	"github.com/offen/envconfig"
+	"mvdan.cc/sh/shell"
 )
 
 type configStrategy string
@@ -126,32 +126,13 @@ func loadConfigsFromEnvFiles(directory string) ([]*Config, error) {
 // source tries to mimic the pre v2.37.0 behavior of calling
 // `set +a; source $path; set -a` and returns the env vars as a map
 func source(path string) (map[string]string, error) {
-	f, err := os.Open(path)
+	vars, err := shell.SourceFile(context.Background(), path)
 	if err != nil {
-		return nil, errwrap.Wrap(err, fmt.Sprintf("error opening %s", path))
+		return nil, errwrap.Wrap(err, "error sourcing conf file")
 	}
-
 	result := map[string]string{}
-	scanner := bufio.NewScanner(f)
-	for scanner.Scan() {
-		line := scanner.Text()
-		line = expand(line, os.LookupEnv)
-		m, err := godotenv.Unmarshal(line)
-		if err != nil {
-			return nil, errwrap.Wrap(err, fmt.Sprintf("error sourcing %s", path))
-		}
-		for key, value := range m {
-			currentValue, currentOk := os.LookupEnv(key)
-			defer func() {
-				if currentOk {
-					os.Setenv(key, currentValue)
-					return
-				}
-				os.Unsetenv(key)
-			}()
-			result[key] = value
-			os.Setenv(key, value)
-		}
+	for key, value := range vars {
+		result[key] = value.String()
 	}
 	return result, nil
 }
diff --git a/cmd/backup/config_provider_test.go b/cmd/backup/config_provider_test.go
index ab033688..234de675 100644
--- a/cmd/backup/config_provider_test.go
+++ b/cmd/backup/config_provider_test.go
@@ -33,8 +33,9 @@ func TestSource(t *testing.T) {
 			"testdata/braces.env",
 			false,
 			map[string]string{
-				"FOO": "${bar:-qux}",
+				"FOO": "qux",
 				"BAR": "xxx",
+				"BAZ": "",
 			},
 		},
 		{
diff --git a/cmd/backup/expand.go b/cmd/backup/expand.go
deleted file mode 100644
index d143f839..00000000
--- a/cmd/backup/expand.go
+++ /dev/null
@@ -1,100 +0,0 @@
-// This code comes from golang standard library:
-// https://github.com/golang/go/blob/0e85fd7561de869add933801c531bf25dee9561c/src/os/env.go#L16-L96
-// This file is explicitly excluded from the top repository license.
-
-// Copyright 2010 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// General environment variables.
-
-package main
-
-import "fmt"
-
-// Expand replaces ${var} or $var in the string based on the mapping function.
-func expand(s string, mapping func(string) (string, bool)) string {
-	var buf []byte
-	// ${} is all ASCII, so bytes are fine for this operation.
-	i := 0
-	for j := 0; j < len(s); j++ {
-		if s[j] == '$' && j+1 < len(s) {
-			if buf == nil {
-				buf = make([]byte, 0, 2*len(s))
-			}
-			buf = append(buf, s[i:j]...)
-			shellNameInput := s[j+1:]
-			name, w := getShellName(shellNameInput)
-			if name == "" && w > 0 {
-				// Encountered invalid syntax; eat the
-				// characters.
-			} else if name == "" {
-				// Valid syntax, but $ was not followed by a
-				// name. Leave the dollar character untouched.
-				buf = append(buf, s[j])
-			} else {
-				replacement, ok := mapping(name)
-				if ok {
-					buf = append(buf, replacement...)
-				} else {
-					// preserve enclosing {}
-					if shellNameInput[0] == '{' {
-						buf = append(buf, fmt.Sprintf("${%s}", name)...)
-					} else {
-						buf = append(buf, fmt.Sprintf("$%s", name)...)
-					}
-				}
-			}
-			j += w
-			i = j + 1
-		}
-	}
-	if buf == nil {
-		return s
-	}
-	return string(buf) + s[i:]
-}
-
-// isShellSpecialVar reports whether the character identifies a special
-// shell variable such as $*.
-func isShellSpecialVar(c uint8) bool {
-	switch c {
-	case '*', '#', '$', '@', '!', '?', '-', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
-		return true
-	}
-	return false
-}
-
-// isAlphaNum reports whether the byte is an ASCII letter, number, or underscore
-func isAlphaNum(c uint8) bool {
-	return c == '_' || '0' <= c && c <= '9' || 'a' <= c && c <= 'z' || 'A' <= c && c <= 'Z'
-}
-
-// getShellName returns the name that begins the string and the number of bytes
-// consumed to extract it. If the name is enclosed in {}, it's part of a ${}
-// expansion and two more bytes are needed than the length of the name.
-func getShellName(s string) (string, int) {
-	switch {
-	case s[0] == '{':
-		if len(s) > 2 && isShellSpecialVar(s[1]) && s[2] == '}' {
-			return s[1:2], 3
-		}
-		// Scan to closing brace
-		for i := 1; i < len(s); i++ {
-			if s[i] == '}' {
-				if i == 1 {
-					return "", 2 // Bad syntax; eat "${}"
-				}
-				return s[1:i], i + 1
-			}
-		}
-		return "", 1 // Bad syntax; eat "${"
-	case isShellSpecialVar(s[0]):
-		return s[0:1], 1
-	}
-	// Scan alphanumerics.
-	var i int
-	for i = 0; i < len(s) && isAlphaNum(s[i]); i++ {
-	}
-	return s[:i], i
-}
diff --git a/cmd/backup/testdata/braces.env b/cmd/backup/testdata/braces.env
index a13a2639..11b5bdc9 100644
--- a/cmd/backup/testdata/braces.env
+++ b/cmd/backup/testdata/braces.env
@@ -1,2 +1,3 @@
 FOO=${bar:-qux}
 BAR=xxx
+BAZ=$NOPE
diff --git a/go.mod b/go.mod
index cedbb00a..2d87cace 100644
--- a/go.mod
+++ b/go.mod
@@ -10,7 +10,6 @@ require (
 	github.com/docker/cli v24.0.9+incompatible
 	github.com/docker/docker v24.0.7+incompatible
 	github.com/gofrs/flock v0.8.1
-	github.com/joho/godotenv v1.5.1
 	github.com/klauspost/compress v1.17.6
 	github.com/leekchan/timeutil v0.0.0-20150802142658-28917288c48d
 	github.com/minio/minio-go/v7 v7.0.67
@@ -22,6 +21,7 @@ require (
 	golang.org/x/crypto v0.19.0
 	golang.org/x/oauth2 v0.17.0
 	golang.org/x/sync v0.6.0
+	mvdan.cc/sh v2.6.4+incompatible
 )
 
 require (
@@ -29,6 +29,7 @@ require (
 	github.com/cloudflare/circl v1.3.7 // indirect
 	github.com/golang-jwt/jwt/v5 v5.2.0 // indirect
 	github.com/golang/protobuf v1.5.3 // indirect
+	golang.org/x/term v0.17.0 // indirect
 	golang.org/x/time v0.0.0-20220609170525-579cf78fd858 // indirect
 	google.golang.org/appengine v1.6.7 // indirect
 	google.golang.org/protobuf v1.31.0 // indirect
diff --git a/go.sum b/go.sum
index d4d4bacd..6f1464d8 100644
--- a/go.sum
+++ b/go.sum
@@ -443,8 +443,6 @@ github.com/ianlancetaylor/demangle v0.0.0-20200824232613-28f6c0f3b639/go.mod h1:
 github.com/inconshreveable/mousetrap v1.0.1/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
 github.com/jarcoal/httpmock v1.2.0 h1:gSvTxxFR/MEMfsGrvRbdfpRUMBStovlSRLw0Ep1bwwc=
 github.com/jarcoal/httpmock v1.2.0/go.mod h1:oCoTsnAz4+UoOUIf5lJOWV2QQIW5UoeUI6aM2YnWAZk=
-github.com/joho/godotenv v1.5.1 h1:7eLL/+HRGLY0ldzfGMeQkb7vMd0as4CfYvUVzLqw0N0=
-github.com/joho/godotenv v1.5.1/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=
 github.com/jpillora/backoff v1.0.0/go.mod h1:J/6gKK9jxlEcS3zixgDgUAsiuZ7yrSoa/FX5e0EB2j4=
 github.com/json-iterator/go v1.1.6/go.mod h1:+SdeFBvtyEkXs7REEP0seUULqWtbJapLOCVDaaPEHmU=
 github.com/json-iterator/go v1.1.9/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=
@@ -473,6 +471,7 @@ github.com/kr/logfmt v0.0.0-20140226030751-b84e30acd515/go.mod h1:+0opPa2QZZtGFB
 github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
 github.com/kr/pretty v0.2.0/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
 github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
+github.com/kr/pretty v0.3.0 h1:WgNl7dwNpEZ6jJ9k1snq4pZsg7DOEN8hP9Xw0Tsjwk0=
 github.com/kr/pretty v0.3.0/go.mod h1:640gp4NfQd8pI5XOwp5fnNeVWj67G7CFk/SaSQn7NBk=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
@@ -599,6 +598,7 @@ github.com/robfig/cron/v3 v3.0.1 h1:WdRxkvbJztn8LMz/QEvLN5sBU+xKpSqwwUO1Pjr4qDs=
 github.com/robfig/cron/v3 v3.0.1/go.mod h1:eQICP3HwyT7UooqI/z+Ov+PtYAWygg1TEWWzGIFLtro=
 github.com/rogpeppe/fastuuid v1.2.0/go.mod h1:jVj6XXZzXRy/MSR5jhDC/2q6DgLz+nrA6LYCDYWNEvQ=
 github.com/rogpeppe/go-internal v1.3.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFRclV5y23lUDJ4=
+github.com/rogpeppe/go-internal v1.6.1 h1:/FiVV8dS/e+YqF2JvO3yXRFbBLTIuSDkuC7aBOAvL+k=
 github.com/rogpeppe/go-internal v1.6.1/go.mod h1:xXDCJY+GAPziupqXw64V24skbSoqbTEfhy4qGm1nDQc=
 github.com/rs/xid v1.5.0 h1:mKX4bl4iPYJtEIxp6CYiUuLQ/8DYMoz0PUdtGgMFRVc=
 github.com/rs/xid v1.5.0/go.mod h1:trrq9SKmegXys3aeAKXMUTdJsYXVwGY3RLcfgqegfbg=
@@ -1259,6 +1259,8 @@ honnef.co/go/tools v0.0.0-20190523083050-ea95bdfd59fc/go.mod h1:rf3lG4BRIbNafJWh
 honnef.co/go/tools v0.0.1-2019.2.3/go.mod h1:a3bituU0lyd329TUQxRnasdCoJDkEUEAqEt0JzvZhAg=
 honnef.co/go/tools v0.0.1-2020.1.3/go.mod h1:X/FiERA/W4tHapMX5mGpAtMSVEeEUOyHaw9vFzvIQ3k=
 honnef.co/go/tools v0.0.1-2020.1.4/go.mod h1:X/FiERA/W4tHapMX5mGpAtMSVEeEUOyHaw9vFzvIQ3k=
+mvdan.cc/sh v2.6.4+incompatible h1:eD6tDeh0pw+/TOTI1BBEryZ02rD2nMcFsgcvde7jffM=
+mvdan.cc/sh v2.6.4+incompatible/go.mod h1:IeeQbZq+x2SUGBensq/jge5lLQbS3XT2ktyp3wrt4x8=
 rsc.io/binaryregexp v0.2.0/go.mod h1:qTv7/COck+e2FymRvadv62gMdZztPaShugOCi3I+8D8=
 rsc.io/quote/v3 v3.1.0/go.mod h1:yEA65RcK8LyAZtP9Kv3t0HmxON59tX3rD+tICJqUlj0=
 rsc.io/sampler v1.3.0/go.mod h1:T1hPZKmBbMNahiBKFy5HrXp6adAjACjK9JXDnKaTXpA=