yq:tldr:38feb

yq: Output the first element in a YAML file that contains only an array (v3).

$ yq read ${filename-yaml} '[0]'

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The command yq read ${filename-yaml} '[0]' is used to extract the value at index 0 from a YAML file using the yq tool.

Here's a breakdown of each component of the command:

yq: It refers to the yq tool, which is a lightweight and flexible command-line YAML processor and query tool.
read: It is a subcommand of yq that specifies that we want to read (or extract) data from a YAML file.
${filename-yaml}: It represents a variable called filename that should be replaced with the actual name of the YAML file you want to read. The .yaml extension indicates that the file is in YAML format.
[0]: It is a YAML query or expression enclosed in square brackets, indicating that we want to extract the value at index 0. In YAML, arrays are denoted by a list of values, and the index of an array starts from 0. So, [0] refers to the first value of an array.

Overall, the command yq read ${filename-yaml} '[0]' retrieves the value at index 0 from the specified YAML file.

This explanation was created by an AI. In most cases those are correct. But please always be careful and never run a command you are not sure if it is safe.

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