Standalone string interpolator and template processor
$ echo '${name} is{{ range seq ${count:-3} }} cool{{ end }}!' | sigil -p name=Sigil
Sigil is cool cool cool!
Sigil is a command line tool for template processing and POSIX-compliant variable expansion. It was created for configuration templating, but can be used for any text processing.
$ curl http://dl.gliderlabs.com/sigil/latest/$(uname -sm|tr \ _).tgz \
| tar -zxC /usr/local/bin
Other releases can be downloaded from Github Releases.
Template text can be provided via STDIN or from a file if provided with the -f
flag. Any other arguments are key-values in the form <key>=<value>
. They are
used as variables.
echo 'Hello, $name' | sigil -p name=Jeff
sigil -p -f config.tmpl var1=foo "var2=Hello world"
There are two forms of variable syntax in Sigil. The first is POSIX style, which among other features allows default values or enforces required values:
$variable
- normal POSIX style${variable:-"default"}
- expansion with default value${variable:?}
- fails when not set
Environment variables are also available as POSIX style variables. This makes Sigil great for quick and simple string interpolation.
The other syntax to use variables is consistent with the rest of the templating
syntax. It uses {{
and }}
to define template expressions. Variable expansion
in this form is simply used as:
{{ $variable }}
You can do much more with this syntax, such as modifier pipelines. All of which is explained below.
Sometimes you want to use sigil to generate text, which uses golang templating itself.
For example if you want to generate packer configuration
your template might contain a lot of {{
and }}
.
Intead of replacing all {{
with {{“{{”}}
, you can change the delimiters,
by setting the SIGIL_DELIMS
environment variable. It is the left and right
delimiter strings, separated by a coma.
SIGIL_DELIMS={{{,}}} sigil -i 'hello {{{ $name }}}' name=packer
There are a number of builtin functions that can be used as modifiers, conditional tests, expansion data sources, and more. There are two references for functions available:
Here are a few examples:
{{ $variable | capitalize }}
{{ include "file.tmpl" "var1=foo" "var2=bar" }}
{{ file "example.txt" | replace "old" "new" }}
{{ json "file.json" | pointer "/Widgets/0/Name" }}
{{ if expr }} true {{ end }}
{{ if expr }} true {{ else }} false {{ end }}
{{ if expr }} true {{ else if expr }} also true {{ end }}
{{ range expr }} element: {{.}} {{ end }}
{{ range expr }} elements {{ else }} no elements {{ end }}
Lots more is possible with this template syntax. Sigil is based on Go's text/template package. You can read full documentation there.