Templates

Templates are content written in minijinja, a templating language close to jinja2.

Standard In-/Output

By default, Contemplate will read a template on standard input, and write to standard output:

$ export NAME="Alice"
$ echo 'Hello, I am {{ name }}!' | contemplate -q --env
Hello, I am Alice!
$

Note

A log message will be printed when reading from standard input, prompting the user to enter a template. This is suppressed in the above example using -q.

The output can be directed to a file by specifying it using --output/-o:

$ export NAME="Bob"
$ echo 'Hello, I am {{ name }}!' | contemplate --env -q -o output.txt
$ cat output.txt
Hello, I am Bob!
$

An input file can be specified as a positional argument:

$ export NAME="Charlie"
$ echo 'Hello, I am {{ name }}!' > template.txt
$ contemplate --env template.txt
Hello, I am Charlie!
$

In-Place Rendering

If the source and target file are identical, in-place rendering can be used. This is enabled using the --in-place/-i command-line parameter. When enabled, multiple templates can be specified as positional arguments, each of which will be overwritten with the rendered context:

contemplate -i template1 template2

A backup of the original template can be automatically made by specifying a backup extension. The following will back-up the templates as template1.bak and template2.bak:

contemplate --in-place=bak template1 template2

Note

To prevent backups from being overwritten by repeat invocations of Contemplate, it will refuse to overwrite backups.

Multiple templates

Multiple templates can be specified on the command line with the --template / -t argument. Each --template argument takes two parameters, the input and output parameter. The following example renders the template contained in input1.txt to output1.txt, and the template contained in input2.txt to output2.txt.

contemplate \
  --template input1.txt output1.txt \
  --template input2.txt output2.txt

Note

The output specification is optional. If left unspecified, output is directed to standard output. To specify standard input or standard output explicitly, - can be passed as a name, e.g. --template - - will cause Contemplate to read a template from standard input and write to standard output. However, it is an error to specify standard input as multiple source or destination values.