How to log docker build installation package errors

Question

When I build a docker image via dockerfile using: docker build -t test/app1 .

The docker builds successfully however, I noticed there are some errors as it installing packages through the build. How can I track/log these package installation errors on linux?

Thanks.

Answer 1

Try docker build -t test/app1 . 2> ~/log.txt

This command will create a log.txt file in the home directory of your user containing standard error output of docker build ... command.