envfilesubst

envfilesubst is a variation of gettext's envsubst, with a different modus operandi.

Firstly, instead of reading the current environment, it instead parses a file in "envfile" format.

Secondly, it will read from standard input and replace all variable references that can be found in the envfile. If variables are not explicitly mentioned in the envfile, the references will be left intact (instead of replacing them with an empty string).

Installation

go install git.netflux.io/rob/envfilesubst@latest

Usage

Given an envfile:

FOO=bar
X=1

Then:

echo "FOO is $FOO and X is ${X}. I don't know $BAR." | envfilesubst -f myenvfile

The output is:

FOO is bar and X is 1. I don't know $BAR.

License

Copyright © 2022 Rob Watson.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.