Make a Shell Command Always Succeed

In bash and many other shells, zero is called successful exit status code, whereas any non-zero codes are failure exit codes. That is to say when a command returns exit code of zero, it’s considered successful; otherwise, it’s considered a failure.

In some situations, one want to make sure a command always return zero, ignoring potential failures. This can be done with the true command:

random_thing || true

The most recent example is in our CI, there is a step to upload code coverage report to codecov.io, but unfortunately their site has been flaky over the past couple weeks, which might cause otherwise successful builds to fail. In this case, we try to upload code coverage report, but if it fails for whatever reason, it’s okay to ignore. So the true command to the rescue:

./.codecov || true

where .codecov is the script for uploading the report.