Use a subshell when cding around in shell scripts

[troyraen]

The better way to do this is to use a subshell. Then you're not changing the implicit global state.

cd templates
bq mk --table ....

-> (cd templates && bq mk --table ....) || exit 5

Originally posted by @tregle in #232 (comment)

We have code in all of our shell scripts that cds around like this. We should replace it as suggested above. This could probably be done by anyone who knows a little bash/shell even if they don't know anything about our repo or project.