j2cli: Jinja2 Command-Line Tool

0.3.10 · maintenance · verified Sat Apr 11

j2cli is a command-line tool that enables Jinja2 templating directly within shell scripts, leveraging the powerful Jinja2 library. It supports various data sources, including INI, YAML, JSON files, and environment variables. The current PyPI version is 0.3.10. While still functional for many use cases, active development on PyPI appears to have slowed, with the last release in 2019, though newer versions (0.3.12b*) are seen in some Linux distributions.

Warnings

breaking j2cli is incompatible with Python 3.12 and newer versions due to its reliance on the removed `imp` module. This prevents `j2cli` from running on Python 3.12+.
Fix: Consider using alternative templating CLIs like `jinjanator` for Python 3.12+, or use an older Python version (e.g., Python 3.11 or earlier) with j2cli.
deprecated The `j2cli` project appears to be largely unmaintained by its original author on PyPI, with the last release being in 2019. While the project is still widely used, the lack of updates has led to critical compatibility issues with newer Python versions.
Fix: For new projects or environments requiring Python 3.12+, it is recommended to evaluate actively maintained alternatives like `jinjanator` or `j2y` (which plans to rename to `j2-cli`).
gotcha To enable YAML data source parsing, `j2cli` requires the `pyyaml` dependency. This is not installed by default and must be explicitly included during installation using `pip install j2cli[yaml]`.
Fix: Install with `pip install j2cli[yaml]` if you plan to use YAML files as data sources.
gotcha When no data file is provided, `j2cli` defaults to reading environment variables (implicitly setting `--format=env`). To explicitly import environment variables into the template as a specific variable (e.g., `env`), use `--import-env VAR` (or `-e VAR`). To import all environment variables into the global scope (which can overwrite existing variables), use `--import-env=`.
Fix: Be mindful of `--format` and `--import-env` options when working with environment variables to avoid unexpected behavior or variable overwrites. Explicitly provide a data source or `--format` when not intending to use environment variables.

Install

pip install j2cli Base installation
pip install j2cli[yaml] With YAML support

Quickstart

This example demonstrates rendering a Jinja2 template (`config.j2`) using data from a JSON file (`data.json`) via the `j2` command-line tool. The `-f json` flag specifies the input data format. The output is printed to stdout.

# Create a Jinja2 template file
cat <<EOF > config.j2
server {
  listen 80;
  server_name {{ app.hostname }};
  root {{ app.webroot }};
  index index.htm;
}
EOF

# Create a JSON data file
cat <<EOF > data.json
{
  "app": {
    "hostname": "localhost",
    "webroot": "/var/www/myproject"
  }
}
EOF

# Render the template using j2cli
j2 -f json config.j2 data.json

# Expected output:
# server {
#   listen 80;
#   server_name localhost;
#   root /var/www/myproject;
#   index index.htm;
# }

view raw JSON →