sed:tldr:7b149

The provided command involves two parts: ${command} and sed -E 's/(apple)/\U\1/g'. Let's understand each part separately:

1. ${command}: This part represents a placeholder for any command that is to be executed. It can be replaced with an actual command or a variable containing a command.

2. | (Pipe symbol): This is a pipeline operator that connects the output of the preceding command to the input of the subsequent command. It allows the output of one command to serve as the input for another command.

3. sed -E 's/(apple)/\U\1/g': Sed is a command-line utility for string manipulation. This part incorporates the sed command along with its options and regular expression sequence.

   • sed is the command itself.

   • -E is an option that enables extended regular expressions, allowing the use of certain syntax and constructs.

   • 's/(apple)/\U\1/g' is a sed script enclosed in single quotes. The script specifies the substitution pattern.

   • s/(apple)/\U\1/g is the substitution pattern in the sed script:

     • s: Indicates that it is a substitute command in sed.
     • (apple): Represents the pattern to match. In this case, it is the word "apple" enclosed in parentheses, which captures it as a group.
     • \U\1: Signifies the replacement pattern. \U is a sed command that converts the following text to uppercase, and \1 represents the first captured group (i.e., "apple").
     • g: Represents the global flag, which means replacing all occurrences of the pattern in each line (not just the first occurrence).

Overall, the given command takes the output of "${command}" and passes it to sed for string substitution. In each line of the output, it searches for the word "apple" and converts it to uppercase using sed's substitution pattern.