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Expression Syntax (GitHub Actions) - CI/CD Glossary Definition

Expression syntax is the ${{ }} mini-language for reading contexts and computing values in workflows.

Expression syntax is the ${{ }} language in GitHub Actions used to read contexts, call built-in functions, and compute values within workflow YAML.

Expressions wrapped in ${{ }} evaluate contexts, operators, and functions like contains, startsWith, and format. They power dynamic values, conditionals, and outputs.

Built-in functions

Useful functions include contains(a, b), startsWith(a, b), format(...), toJSON(...), and the status checks success(), failure(), always(), and cancelled().

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