YAML - Shell/Bash

YAML (short for "YAML Ain't Markup Language") is a human-readable data serialization language that is commonly used for configuration files, data exchange between languages, and so on. In Shell/Bash, YAML files can be parsed and manipulated using commands and tools like awk, sed, and grep, making them a powerful tool for scripting and automation.

Installing YAML

Before working with YAML files in Shell/Bash, you need to install a YAML parser. Some popular ones include:

• jq: A command-line tool for parsing JSON, which can also handle simple YAML files.
• yq: A command-line tool specifically for parsing and manipulating YAML files.
• yaml2json: A Node.js module for converting YAML to JSON.

Reading and Writing YAML Files

To read the contents of a YAML file in Shell/Bash, you can use the cat command:

cat file.yml

This will output the contents of the file to the terminal.

To write data to a YAML file, you can use a text editor or the echo command in conjunction with a heredoc:

cat <<EOF > file.yml
key1: value1
key2: value2
EOF

This will create a new YAML file called file.yml with the specified key-value pairs.

Manipulating YAML Data

To manipulate YAML data in Shell/Bash, you can use various tools and techniques. Here are a few examples:

• awk: You can use awk to search for and replace values in a YAML file. For example, to replace "oldvalue" with "newvalue" in a file called file.yml, you can use:

  awk '{gsub(/oldvalue/,"newvalue")}1' file.yml > newfile.yml
  

• sed: Similar to awk, you can use sed to search for and replace values in a YAML file. For example, to replace "oldvalue" with "newvalue" in a file called file.yml, you can use:

  sed -i 's/oldvalue/newvalue/g' file.yml
  

• grep: You can use grep to search for specific values in a YAML file. For example, to search for all instances of "value1" in a file called file.yml, you can use:

  grep -r "value1" file.yml
  

These are just a few examples of how you can use Shell/Bash to manipulate YAML data. With the right tools and techniques, you can easily automate complex tasks and workflows using YAML.