passenv

A shell command, like env, to run a program in an environment modified by values read from standard input.

Motivation

The immediate problem passenv intends to solve is the sharing of secrets between shell programs, notably those encrypted by and accessible via the password store pass.

However, passenv is applicable to any situation where values one might set in a program environment via env are most conveniently read from standard input.

For example, the values stored in pass might be organized and accessible in the following manner:

$ pass show db/admin
p@ssw0r!d
Username: db_admin

With pass, we can store the password in the system clipboard — (with a timeout) — and apply it where we need it. …​Or we can store these secrets in our tmux buffer. …​Etc., etc.

But for programs which are able to read these secrets from their environment, this is a far more efficient, more reliable, and reasonably secure interface for doing so:

$ pass show db/admin | passenv PGPASSWORD PGUSER psql -h myserver mydb
mydb=>

(Moreover, say for a script which invokes psql multiple times, this is far superior to entering the password multiple times — particularly so as it might be cleared from your clipboard for security.)

Installation

passenv requires Python.

You’ll likely want to install it to a directory on your PATH, such as ~/.local/bin/.

Use

Please refer to passenv --help.

passenv intends to largely duplicate the interface of env.

Note that values read from standard input which conform to the pattern in the example above, namely — 

Name: value

 — are trimmed to remove the label Name: . The environment name intended for this value must be defined per invocation.