Which symbol is commonly used for executing a command inside some other command in Shell Scripting?

The most commonly used symbol for executing a command inside another command in Shell Scripting is the syntax that uses the dollar sign followed by parentheses, represented as $(). This notation is known as command substitution. It allows the output of one command to be used as an argument in another command.

For instance, if you want to retrieve the current date and use it as a part of a filename, you might write something like filename="backup_$(date +%Y-%m-%d).tar.gz". Here, the date command executes first, and its output replaces $(date +%Y-%m-%d) in the assignment to filename, resulting in a dynamically generated filename.

Command substitution can also be done using backticks (``), but the $() syntax is generally preferred due to its improved readability and ability to nest commands more easily. This characteristic makes it a powerful tool in Shell Scripting for ensuring that commands can be executed in a modular and efficient manner.