Docker build is not recognising the -e flag for the echo command

[kalpaitch]

Description

I'm not sure how to categorise this but it seems like unexpected behaviour. I'm running a simple command such as echo -e "BEGINNING OF FILE\n\n" > .tmpfile

When I run this from the docker image it outputs as expected. When I run this within a 'RUN' command in the Dockerfile it outputs the '-e' flag as part of the output e.g. "-e BEGINNING OF FILE".

I have no idea why it's outputting the -e flag directly.

Reproduce

Add this step to the Docker file:

RUN echo -e "BEGINNING OF FILE\n\n" > .tmpfile

Expected behavior

The output should be:

BEGINNING OF FILE

But is actually:

-e BEGINNING OF FILE

docker version

Client: Docker Engine - Community
 Version:           25.0.3
 API version:       1.44
 Go version:        go1.21.6
 Git commit:        4debf41
 Built:             Tue Feb  6 21:13:09 2024
 OS/Arch:           linux/amd64
 Context:           default

Server: Docker Engine - Community
 Engine:
  Version:          25.0.3
  API version:      1.44 (minimum version 1.24)
  Go version:       go1.21.6
  Git commit:       f417435
  Built:            Tue Feb  6 21:13:09 2024
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          1.6.28
  GitCommit:        ae07eda36dd25f8a1b98dfbf587313b99c0190bb
 runc:
  Version:          1.1.12
  GitCommit:        v1.1.12-0-g51d5e94
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

docker info

Client: Docker Engine - Community
 Version:    25.0.3
 Context:    default
 Debug Mode: false
 Plugins:
  buildx: Docker Buildx (Docker Inc.)
    Version:  v0.12.1
    Path:     /usr/libexec/docker/cli-plugins/docker-buildx
  compose: Docker Compose (Docker Inc.)
    Version:  v2.24.6
    Path:     /usr/libexec/docker/cli-plugins/docker-compose
  scout: Docker Scout (Docker Inc.)
    Version:  v1.0.8
    Path:     /home/andrew/.docker/cli-plugins/docker-scout

Server:
 Containers: 4
  Running: 4
  Paused: 0
  Stopped: 0
 Images: 11
 Server Version: 25.0.3
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Using metacopy: false
  Native Overlay Diff: true
  userxattr: false
 Logging Driver: json-file
 Cgroup Driver: systemd
 Cgroup Version: 2
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local splunk syslog
 Swarm: inactive
 Runtimes: io.containerd.runc.v2 runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: ae07eda36dd25f8a1b98dfbf587313b99c0190bb
 runc version: v1.1.12-0-g51d5e94
 init version: de40ad0
 Security Options:
  apparmor
  seccomp
   Profile: builtin
  cgroupns
 Kernel Version: 6.2.0-39-generic
 Operating System: Ubuntu 23.04
 OSType: linux
 Architecture: x86_64
 CPUs: 16
 Total Memory: 62.52GiB
 Name: kalpaitch-spinach
 ID: a160b708-c811-46e9-9c47-389514f4b548
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 Experimental: false
 Insecure Registries:
  127.0.0.0/8
 Live Restore Enabled: false

Additional Info

No response

[athulnair02]

Hi, I would like to work on this, is there a good place to start?

[thaJeztah]

I'm not able to reproduce this issue using alpine as base-image;

docker build -t foo -<<'EOF'
FROM alpine
RUN echo -e "BEGINNING OF FILE\n\n" > .tmpfile
EOF

Build runs successfully;

[+] Building 1.5s (7/7) FINISHED                                                                                                                                                                           docker:desktop-linux
 => [internal] load build definition from Dockerfile                                                                                                                                                                       0.0s
 => => transferring dockerfile: 96B                                                                                                                                                                                        0.0s
 => [internal] load metadata for docker.io/library/alpine:latest                                                                                                                                                           0.0s
 => [internal] load .dockerignore                                                                                                                                                                                          0.0s
 => => transferring context: 2B                                                                                                                                                                                            0.0s
 => [1/2] FROM docker.io/library/alpine:latest@sha256:c5b1261d6d3e43071626931fc004f70149baeba2c8ec672bd4f27761f8e1ad6b                                                                                                     1.2s
 => => resolve docker.io/library/alpine:latest@sha256:c5b1261d6d3e43071626931fc004f70149baeba2c8ec672bd4f27761f8e1ad6b                                                                                                     1.2s
 => [auth] library/alpine:pull token for registry-1.docker.io                                                                                                                                                              0.0s
 => [2/2] RUN echo -e "BEGINNING OF FILE\n\n" > .tmpfile                                                                                                                                                                   0.1s
 => exporting to image                                                                                                                                                                                                     0.1s
 => => exporting layers                                                                                                                                                                                                    0.0s
 => => exporting manifest sha256:07e9b08ca1e01a821c0779ed887a2ad47622da64c8bd558c757ada84bfdb97ab                                                                                                                          0.0s
 => => exporting config sha256:e8769b3ba4c8f5e05d3c2b38644985cc74fb123b221a79fd99635b7663815811                                                                                                                            0.0s
 => => exporting attestation manifest sha256:c93bcc769d1be9eca9549c10fe9828a49f922e8abc2c7423cbf6a5ff719b8c99                                                                                                              0.0s
 => => exporting manifest list sha256:97cab80709c4b973b084d9066f472d9dd242a395646bc6f9dfcfc0099b4f0fd3                                                                                                                     0.0s
 => => naming to docker.io/library/foo:latest                                                                                                                                                                              0.0s
 => => unpacking to docker.io/library/foo:latest                                                                                                                                                                           0.0s

And checking the file shows the expected content;

docker run --rm foo cat /.tmpfile
BEGINNING OF FILE

However, the RUN command itself is executed in a container, so it depends on what base-image you're using; my example used alpine, but perhaps it doesn't work with other images; what image are you using as base-image?

[fozboz]

I just came across this, too, using Ubuntu 22.04 base image. The build is run in a standard sh shell. When echo is invoked from sh it will have the -e behaviour by default.

So, at least for my case, I just omitted the -e and got the results I expected.