zsh:tldr:ba0fd

The command zsh -c "${echo Hello world}" is an example of running a command in the Zsh shell.

Let's break down the command step by step:

1. zsh: This is the command to invoke the Zsh shell.

2. -c: The -c option allows you to provide a command string or script to be executed by the shell.

3. "${echo Hello world}": In this particular command, the command string is ${echo Hello world}. It is enclosed within double quotes to prevent any variable expansion by the current shell.

The ${echo Hello world} is not a valid command itself, but it utilizes variable expansion syntax. Here is how it breaks down:

• ${...}: This syntax is used for variable expansion in shell scripting.
• echo: It is a command used to display text or values.
• Hello world: These are the arguments or parameters provided to the echo command.

However, since $ is inside quotes, variable expansion does not actually occur here. Instead, the Zsh shell treats the entire ${echo Hello world} as a literal string and attempts to execute it as a command. As ${echo Hello world} is not a valid command, it will result in an error.

To successfully run the command, it could be modified like this:

zsh -c 'echo "Hello world"'

In this case, the single quotes ensure that the echo "Hello world" part is treated as a literal string and passed to the Zsh shell for execution.