August 2012
Intermediate to advanced
624 pages
17h 11m
Polish
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4.8. Wyświetlenie komunikatów o błędach
Problem
Skrypt powinien generować komunikaty o nieprawidłowościach w swoim działaniu. Informacje te powinny być wyświetlane za każdym razem, gdy którekolwiek z poleceń nie zostanie wykonane poprawnie. Jednak duża liczba instrukcji if zmniejsza czytelność kodu.
Rozwiązanie
Często stosowaną techniką generowania komunikatów o błędach lub wyświetlania informacji w czasie debugowania skryptu jest stosowanie poleceń rozdzielanych operatorem ||. Oto przykład:
$ polecenie || printf "%b" "polecenie zakończone błędem. Radź sobie sam\n"Analiza
Zgodnie z prezentowanymi wcześniej informacjami operator && nie dopuszcza do ustalenia wartości drugiego wyrażenia, jeżeli pierwsze nie jest prawdziwe. Podobnie działa operator
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.