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Simple Issue Language (SIL) is an easy to learn scripting language (see SIL syntax) that is used by some of our certain apps. 

Example

For example with SIL and Power Scripts for Jira app you can create a post function that automatically creates a sub-task.

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For the language syntax, check out the syntax page.

Jira standard variables

SIL has a list of standard variables which you can use to change issues fields.

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