The point of this project boils down to two things:

• Hy is amazingly cool.
• Jinja2 is beautiful and extremely useful.

I want to use Jinja2 from the command line and I'm sure others have wanted the same thing. Sometimes you just want to write a super simple template really quick and pipe values to it from the command line. J2DO is that tool. Now you can use Jinja2 templates inline or from .j2 files and pipe or pump data to them from the command line. In addition, JQ is a fantastic partner to J2Do because you can use it to transform datasets from disparate programs into something that your Jinja2 template can understand.

pip install git+https://github.com/Pebaz/j2do.git

Example template file scuttle.j2:

{% for i in range(times) %}
    Hello {{ name }}!
{% endfor %}

Render this template with command line arguments:

j2do scuttle.j2 name="'Pebaz'" times=3

Render this template with JSON input:

{
    "name" : "Yelbu",
    "times" : 3
}

j2do scuttle.j2 --json answers.json

Render this template with YAML input:

name: "Nodibu"
times: 3

j2do scuttle.j2 --yml answers.yml

Render this template with a text file containing key-value pairs:

name="Protodip"
times=3

j2do scuttle.j2 --kv answers.txt

Process a given template with Environment Variable input:

set j2_name="'Pebaz'"
set j2_times=3
j2do scuttle.j2 --env

Process a given template with STDIN input:

cat answers.yml | j2do scuttle.j2 --yml -
cat answers.json | j2do scuttle.j2 --json -
cat answers.txt | j2do scuttle.j2 --kv -

Use JQ along with J2DO:

{
    "name" : "Yelbu",
    "times" : 3,
    "extra" : "not used"
}

cat answers.json | jq "del(.extra)" | j2do scuttle.j2 --json -

Use J2DO as a library:

from j2do import j2do

data = {"name" : "'Pebaz'", "times" : 3}

out = j2do(
    template="mytemplate.j2",   # Template to load
    data=data,                  # Data to pass to template
    include=["templates"],      # Where to find templates (accepts list)
    outfile=None                # Return text don't output file (defaults to None)
)

print(out)

The template rendering environment comes preloaded with constants you can use to create more attractive terminal output.

Hello {{_CLRfg}}{{name}}{{_CLRreset}}!

This will output "Hello Pebaz!" to the screen with only the name "Pebaz" highlighted green. Look into term_colors.hy for the list of possible colors. Foreground and Background colors are supported.

• When passing in parameters from the command line, values should be valid Python values. Strings should be double-quoted because the terminal will strip them.

  # Work
  j2do scuttle.j2 name="'python understands this'"
  
  # Doesn't Work
  j2do scuttle.j2 name="but not this"
  
  # Example list
  j2do scuttle.j2 items="[1, 2, 'this is a string']"

• For another similar project, check out: J2CLI

• The name j2do comes from sudo 😉

• Make default syntax: j2do "inline template" ... and files: j2do -f temp.j2 ...