Run a script in Dockerfile
Try to create script with ADD
command and specification of working directory
Like this("script" is the name of script and /root/script.sh
is where you want it in the container, it can be different path:
ADD script.sh /root/script.sh
In this case ADD
has to come before CMD
, if you have one
BTW it's cool way to import scripts to any location in container from host machine
In CMD
place [./script]
It should automatically execute your script
You can also specify WORKDIR
as /root
, then you'l be automatically placed in root, upon starting a container
It's best practice to use COPY
instead of ADD
when you're copying from the local file system to the image. Also, I'd recommend creating a sub-folder to place your content into. If nothing else, it keeps things tidy. Make sure you mark the script as executable using chmod
.
Here, I am creating a scripts
sub-folder to place my script into and run it from:
RUN mkdir -p /scripts
COPY script.sh /scripts
WORKDIR /scripts
RUN chmod +x script.sh
RUN ./script.sh
In addition to the answers above:
If you created/edited your .sh script file in Windows, make sure it was saved with line ending in Unix format. By default many editors in Windows will convert Unix line endings to Windows format and Linux will not recognize shebang (#!/bin/sh) at the beginning of the file. So Linux will produce the error message like if there is no shebang.
Tips:
- If you use Notepad++, you need to click "Edit/EOL Conversion/UNIX (LF)"
- If you use Visual Studio, I would suggest installing "End Of Line" plugin. Then you can make line endings visible by pressing Ctrl-R, Ctrl-W. And to set Linux style endings you can press Ctrl-R, Ctrl-L. For Windows style, press Ctrl-R, Ctrl-C.
RUN
and ENTRYPOINT
are two different ways to execute a script.
RUN
means it creates an intermediate container, runs the script and freeze the new state of that container in a new intermediate image. The script won't be run after that: your final image is supposed to reflect the result of that script.
ENTRYPOINT
means your image (which has not executed the script yet) will create a container, and runs that script.
In both cases, the script needs to be added, and a RUN chmod +x /bootstrap.sh
is a good idea.
It should also start with a shebang (like #!/bin/sh
)
Considering your script (bootstrap.sh
: a couple of git config --global
commands), it would be best to RUN
that script once in your Dockerfile
, but making sure to use the right user (the global git config
file is %HOME%/.gitconfig
, which by default is the /root
one)
Add to your Dockerfile:
RUN /bootstrap.sh
Then, when running a container, check the content of /root/.gitconfig
to confirm the script was run.