Progress bars #

If your tasks takes too long, maybe because its complexity or because it depends on the Network, it’s reasonable to show progress with a Progress bar, that won’t be included in the final output, or won’t be outputted in an non-interactive (non-tty) terminal.

See How to make a progress bar?

Error messages #

… See: debugging

Success message #

Unless the result of the CLI command should be the output, like in case with ls, consider no output. If no errors or unexpected behaviors happened during the CLI’s execution, exiting your program with a 0 exit code might be enough. It’s tempting to print out a success message, or a message describing a new state after command finished, but maybe it’s not needed. Consider cp command - EXAMPLE OF CP WITH EXTRA OUTPUT

https://www.linuxtopia.org/online_books/programming_books/art_of_unix_programming/ch11s09.html