First, we'll use a script that does one simple thing. It reads the config file, validates its format, and outputs its contents without any blank lines or comments. The script is significantly more complex than the little snippet we had before, although we're only adding a few modest features. This is a common pattern which should be carefully considered: adding a couple of small features results in a very large increase in complexity. In this case, the added complexity is justified, but we shouldn't make the decision lightly.
The script is called env-echo.sh and here is what it contains:
#!/usr/bin/env bash # Echoes environment variables from a file # -- ignores comment lines # -- ignores blank lines # -- validates format of each line to ensure a proper variable declaration # -- requires variable names to have a prefix to avoid collisions # -- skips variables in file if already set, allowing overrides # safety settings to ensure errors in this script are caught...