dash:tldr:23161

This command runs the dash shell with the -c flag and a specified command.

The dash command is a minimalistic Unix shell that is often used as the default /bin/sh shell on many Unix-like systems.

The -c flag allows you to specify a command to be executed by the shell. In this case, the command is "${echo 'dash is executed'}".

The command within the quotes is an attempt to use variable substitution with the ${} syntax. However, since it is written within double quotes, the ${} syntax is treated as a literal string. Therefore, the command executed by dash will be exactly ${echo 'dash is executed'}.

In essence, the command is trying to execute a dash shell, passing the string ${echo 'dash is executed'} as the command to be executed. However, since the ${} syntax is not expanded correctly in this case, the command will result in an error.