这是的行为bash。Docker仍在运行带有外壳的命令，您可以通过检查来识别该外壳：
$ docker inspect test-centos-entrypoint --format '{{.Config.Entrypoint}}'
[/bin/sh -c ping localhost]
您可以看到/ bin / sh的版本（请注意GNU bash部分）：
$ docker exec -it quicktest /bin/sh --version
GNU bash, version 4.2.46(2)-release (x86_64-redhat-linux-gnu)
Copyright (C) 2011 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software; you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
/ bin / sh的ubuntu版本（可能是破折号）甚至不支持该--version标志，并且未链接到bash。但是，如果您将ubuntu映像更改为使用bash而不是/ bin / sh，则会看到与centos匹配的行为：
$ cat df.ubuntu-entrypoint
FROM ubuntu:trusty
ENTRYPOINT [ "/bin/bash", "-c", "ping localhost" ]
$ DOCKER_BUILDKIT=0 docker build -t test-ubuntu-entrypoint -f df.ubuntu-entrypoint .
Sending build context to Docker daemon 23.04kB
Step 1/2 : FROM ubuntu:trusty
---> 67759a80360c
Step 2/2 : ENTRYPOINT [ "/bin/bash", "-c", "ping localhost" ]
---> Running in 5c4161cafd6b
Removing intermediate container 5c4161cafd6b
---> c871fe2e2063
Successfully built c871fe2e2063
Successfully tagged test-ubuntu-entrypoint:latest
$ docker run -d --name quicktest2 --rm test-ubuntu-entrypoint
362bdc75e4a960854ff17cf5cae62a3247c39079dc1290e8a85b88114b6af694
$ docker exec -it quicktest2 ps -ef
UID PID PPID C STIME TTY TIME CMD
root 1 0 0 13:05 ? 00:00:00 ping localhost
root 8 0 0 13:05 pts/0 00:00:00 ps -ef
602392714
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