System Operators

The system operator allows you to run an external command and use its output as a value in your expression.

Security warning: The system operator is disabled by default. You must explicitly pass --security-enable-system-operator to use it.

Note: When enabled, the system operator can replicate the functionality of env and load operators via external commands. Enabling it effectively overrides --security-disable-env-ops and --security-disable-file-ops.

Usage

bash

yq --security-enable-system-operator --null-input '.field = system("command"; "arg1")'

The operator takes:

A command string (required)
An argument (or an array of arguments), separated from the command by ; (optional)

The current matched node's value is serialised and piped to the command via stdin. The command's stdout (with trailing newline stripped) is returned as a string.

Disabling the system operator

The system operator is disabled by default. When disabled, an error is returned instead of running the command, consistent with --security-disable-env-ops and --security-disable-file-ops.

Use --security-enable-system-operator flag to enable it.