diff --git a/Dockerfile b/Dockerfile
index 145097803..c78bd3706 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,14 +1,13 @@
-FROM golang:1.18-alpine as builder
-RUN apk update && \
-    apk add --virtual build-deps make git
+FROM golang:1.20-alpine as builder
+RUN apk add --no-cache --virtual build-deps make git
 # Build Elvish
 COPY . /go/src/src.elv.sh
 RUN make -C /go/src/src.elv.sh get
 
-FROM alpine:3.13
-COPY --from=builder /go/bin/elvish /bin/elvish
+FROM alpine:3.18
 RUN adduser -D elf
-RUN apk update && apk add tmux mandoc man-pages vim curl git
+RUN apk update && apk add tmux mandoc man-pages vim curl sqlite git
+COPY --from=builder /go/bin/elvish /bin/elvish
 USER elf
 WORKDIR /home/elf
 CMD ["/bin/elvish"]
diff --git a/pkg/eval/builtin_fn_str.go b/pkg/eval/builtin_fn_str.go
index a97179507..13c2572db 100644
--- a/pkg/eval/builtin_fn_str.go
+++ b/pkg/eval/builtin_fn_str.go
@@ -67,11 +67,29 @@ func base(fm *Frame, b int, nums ...int) error {
 	return nil
 }
 
-var eawkWordSep = regexp.MustCompile("[ \t]+")
+type eawkOpt struct {
+	Sep   string
+	Posix bool
+}
+
+func (o *eawkOpt) SetDefaultOptions() {
+	o.Posix = false
+	o.Sep = "[ \t]+"
+}
 
-func eawk(fm *Frame, f Callable, inputs Inputs) error {
+func eawk(fm *Frame, opts eawkOpt, f Callable, inputs Inputs) error {
 	broken := false
+	var eawkWordSep *regexp.Regexp
 	var err error
+	if opts.Posix {
+		eawkWordSep, err = regexp.CompilePOSIX(opts.Sep)
+	} else {
+		eawkWordSep, err = regexp.Compile(opts.Sep)
+	}
+	if err != nil {
+		return err
+	}
+
 	inputs(func(v any) {
 		if broken {
 			return
diff --git a/pkg/eval/builtin_fn_str_test.go b/pkg/eval/builtin_fn_str_test.go
index 168dc4823..8bd36c2d1 100644
--- a/pkg/eval/builtin_fn_str_test.go
+++ b/pkg/eval/builtin_fn_str_test.go
@@ -87,5 +87,17 @@ func TestEawk(t *testing.T) {
 				}
 			}
 		`).Puts("a", "c", "e"),
+		// Parsing docker image ls output with custom separator:
+		That(`
+	to-lines [
+		'REPOSITORY                TAG          IMAGE ID      CREATED         SIZE'
+		'<none>                    <none>       265c2d25a944  16 minutes ago  67.5 MB'
+		'<none>                    <none>       26408a88b236  16 minutes ago  389 MB'
+		'localhost/elvish_eawk     latest       0570db4e3eaa  32 hours ago    67.5 MB'
+		'localhost/elvish          latest       59b1eec93ab7  33 hours ago    67.5 MB'
+		'docker.io/library/golang  latest       015e6b7f599b  46 hours ago    838 MB'
+		'docker.io/library/golang  1.20-alpine  93db368a0a9e  3 days ago      266 MB'
+	] | eawk &sep=" [ ]+" {|0 1 2 3 4 5| put $5 }
+		`).Puts("SIZE", "67.5 MB", "389 MB", "67.5 MB", "67.5 MB", "838 MB", "266 MB"),
 	)
 }