Using the RUN instruction in a Dockerfile with ‘source’ does not work

by

Original Answer

FROM ubuntu:14.04
RUN rm /bin/sh && ln -s /bin/bash /bin/sh

This should work for every Ubuntu docker base image. I generally add this line for every Dockerfile I write.

Edit by a concerned bystander

If you want to get the effect of “use bash instead of sh throughout this entire Dockerfile”, without altering and possibly damaging* the OS inside the container, you can just tell Docker your intention. That is done like so:

SHELL ["/bin/bash", "-c"]

* The possible damage is that many scripts in Linux (on a fresh Ubuntu install grep -rHInE '/bin/sh' / returns over 2700 results) expect a fully POSIX shell at /bin/sh. The bash shell isn’t just POSIX plus extra builtins. There are builtins (and more) that behave entirely different than those in POSIX. I FULLY support avoiding POSIX (and the fallacy that any script that you didn’t test on another shell is going to work because you think you avoided basmisms) and just using bashism. But you do that with a proper shebang in your script. Not by pulling the POSIX shell out from under the entire OS. (Unless you have time to verify all 2700 plus scripts that come with Linux plus all those in any packages you install.)

More detail in this answer below. https://stackoverflow.com/a/45087082/117471

More Related Contents:

  1. How to pass arguments to Shell Script through docker run
  2. Docker: How to use bash with an Alpine based docker image?
  3. docker entrypoint running bash script gets “permission denied”
  4. How to set uid and gid in Docker Compose?
  5. While loop stops reading after the first line in Bash
  6. How can I compare numbers in Bash?
  7. Pipe output and capture exit status in Bash
  8. Redirect stderr and stdout in Bash [duplicate]
  9. How to mount a host directory in a Docker container
  10. Why equal to operator does not work if it is surrounded by space?
  11. Which characters need to be escaped when using Bash?
  12. Capturing Groups From a Grep RegEx
  13. Why does “local” sweep the return code of a command?
  14. bash : Illegal number
  15. Batch renaming files with Bash
  16. Shell redirection i/o order
  17. How to generate random number in Bash?
  18. Delete files older than 10 days using shell script in Unix [duplicate]
  19. Simulating ENTER keypress in bash script
  20. How to make awk ignore the field delimiter inside double quotes? [duplicate]
  21. How do I know when my docker mysql container is up and mysql is ready for taking queries?
  22. Passing arguments by reference
  23. Get current directory or folder name (without the full path)
  24. How do file descriptors work?
  25. Execute a shell function with timeout
  26. Using Bash to display a progress indicator (spinner) [duplicate]
  27. Use GNU find to show only the leaf directories
  28. Get the name of the caller script in bash script
  29. Missing Carriage Return in Docker for Mac Containers
  30. What does `kill -0 $pid` in a shell script do?

Leave a Comment