Tempered
======
[](https://hackage.haskell.org/package/tempered)
A dead-simple templating utility for simple shell interpolation.
Use at your own risk and only on trusted templates.
```bash
$ tempered --help
Tempered - Templating engine based on shell interpolation
Usage: tempered [templates]
Interpolate templates to stdout
Available options:
templates The templates to interpolate
-h,--help Show this help text
```
Here's a simple use-case:
```md
{{ # inside "post.md" }}
# My Blog Post
by {{ echo $AUTHOR }}
Published on {{ date +'%B %d, %Y' }}
Here's my blog post!
---
{{ cat ./footer.md | tr 'a-z' 'A-Z' }}
```
```md
{{ # inside "footer.md" }}
Copyright 2017 Chris Penner
Check me out on twitter @chrislpenner!
See you next time!
```
Then we can render the template with
```
tempered ./post.md
# OR
cat ./post.md | tempered
```
to get:
```
# My Blog Post
by Chris Penner
Published on April 22, 2017
Here's my blog post!
---
COPYRIGHT 2017 CHRIS PENNER
CHECK ME OUT ON TWITTER @CHRISLPENNER!
SEE YOU NEXT TIME!
```
If you want you can add a shebang to the top of your template and just run it
as an executable, tempered will strip the shebang for you automagically:
> test.txt
```
#!/path/to/tempered
interpolate {{ echo $THIS }}
```
```bash
$ chmod +x test.txt
$ export THIS="that"
$ ./test.txt
interpolate that
```
Shell not powerful enough for you? No problem! Use all your favourite languages and
tools; See the FAQ or examples to see how to integrate with scripts (spoilers, just call them like you do in bash!)
[**Examples Here**](https://github.com/ChrisPenner/tempered/tree/master/examples)
Installation
============
Mac and Linux binaries are provided [HERE](https://github.com/ChrisPenner/tempered/releases/latest);
### Homebrew On Mac
```
brew update
brew install ChrisPenner/tools/tempered
```
### Stack
If you're familiar with Haskell Stack:
```
stack update && stack install tempered
```
FAQ
=====
There's really not much to it; parses the file and runs anything
inside `{{ }}` as a shell expression and pipes stdout into its spot.
If you're clever you can do pretty much anything you want with this.
### Variables?
Sure; It's bash.
```bash
Hello, my name is {{echo $USER}}
```
You can set up environment overrides in `env.yaml`, tempered looks up through
the file-system to find an `env.yaml` from the cwd NOT the template location.
Here's an example env.yaml; we can do simple strings or commands here; just make
sure to quote any entries that start with `{{` or the YAML parser gets mad.
> env.yaml
```yaml
PROJECT: Tempered
DATE: "{{ date +'%B %d, %Y' }}"
```
Then you can use them just like normal variables.
### For Loops?
It's bash; go for it:
```bash
{{ for i in 99 98 97 ; do
cat <<EOF
$i bottles of beer on the wall
EOF
done }}
```
> output:
```
99 bottles of beer on the wall
98 bottles of beer on the wall
97 bottles of beer on the wall
```
### Other Scripts/Tools?
Duh! Interpolation works like a shell, just call the scripts or binaries you want!
Here we'll use a simple python script to spice things up!
```python
# favourites.py
import sys
print(" and ".join(sys.argv[1:]) + ",")
print("These are a few of my favourite things")
```
```
# My Favourite Things
{{ python favourites.py Gumdrops Roses Whiskers Kittens }}
When the dog bites
When the bee stings
When I'm feeling sad
I simply remember my favourite things
And then I don't feel so bad
```
Output:
```
# My Favourite Things
Gumdrops and Roses and Whiskers and Kittens,
These are a few of my favourite things
When the dog bites
When the bee stings
When I'm feeling sad
I simply remember my favourite things
And then I don't feel so bad
```
### \_\_: command not found?
Chances are you're forgetting to echo an env-var;
`{{ $TITLE }}` will try to run the contents of `$TITLE` as a command, you want
`{{ echo "$TITLE" }}`.
### Isn't this whole thing a security risk?
Probably.