why docker run command under /bin/sh?????

[lichuan]

why docker run command with default /bin/sh, why? why? why? , I think /bin/bash is good than /bin/sh, if you run under /bin/sh, some command will produce error. please tell me why docker run command with /bin/sh instead of /bin/bash??????

[LK4D4]

@lichuan command is image entity, not docker. So, all questions to image authors(I don't know what image do you use).
And in most cases /bin/sh is symlink to /bin/bash

[lichuan]

for example when i write the below to dockerfile:

RUN echo -e "passwd\npasswd\n" | smbpasswd -a -s

when I build this dockerfile, error will happen.

[lichuan]

if default shell is /bin/bash, there is no error. so why docker RUN command under /bin/sh????

[LK4D4]

@lichuan try `RUN ["/bin/bash", "-c", ...]

[lichuan]

@LK4D4

if docker RUN command under /bin/bash defaultly, the dockerfile can be very simple, RUN ["/bin/bash", "-c", ...] is ugly......

[phemmer]

@lichuan sh is defined in the POSIX standard, while bash is not. Thus for highest compatibility, bash cannot be relied upon.

[SvenDowideit]

As a specific example - the busybox image doesn't have bash - the boot2docker iso doesn't have bash either sh exists and is the default for a reason.

[unclejack]

The builder documentation already states that /bin/sh is used for commands which look like RUN foo.

I'll close this issue since the only reason for keeping it open was to make the needed changes to the docs.

[odykyi]

add the first line to your *.sh file

#!/bin/sh

it works in docker