I'm doing a lab and can't understand this:

Kubectl has support for auto-completion allowing you to discover the available options. This is applied to the current terminal session with source <(kubectl completion bash)

The cmd:

source <(kubectl completion bash)

sources-in what?

CodePudding user response：

• source (synonym for .) is a bash built in command which executes the given file in the current shell environment
• <(command ...) is process substitution - the output of the commands are passed as a file
• bash completion is implemented with shell functions, which must be set in the current shell environment
• You can view the code that's executed to set up the completion functions: kubectl completion bash

CodePudding user response：

Read and execute the generated completion script (kubectl completion bash) in your current shell.

CodePudding user response：

Using source, it runs within the existing shell, any variables/functions created or modified will remain available after the command completes.

In contrast you just run just the command, then a separate subshell would be spawned to run the command. When the command ends, you will not see the variables/functions in the current shell.

<( expression ) will attach the output of expression to the stdin of an application/program.

So the command will run kubectl completion bash within the existing shell instead of a separate subshell.