August 2012
Intermediate to advanced
624 pages
17h 11m
Polish
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3.8. Wprowadzanie haseł
Problem
Użytkownik musi wprowadzić hasło, ale nie powinno ono zostać wyświetlone na ekranie.
Rozwiązanie
read –s –p "hasło: " PASSWD printf "%b" "\n"
Analiza
Dodana do polecenia read opcja –s zapobiega powieleniu wpisywanych znaków na ekranie, a opcja –p odpowiada za wyświetlenie komunikatu podanego jako parametr polecenia przed pobraniem danych od użytkownika.
Wprowadzony przez użytkownika wiersz danych jest przekazywany do zmiennej środowiskowej o nazwie $PASSWD.
Za instrukcją read występuje polecenie printf wymuszające przejście do następnego wiersza. Polecenie printf jest niezbędne, ponieważ instrukcja read –s wyłącza wyświetlanie na ekranie jakichkolwiek znaków. Oznacza to, że po naciśnięciu przez użytkownika klawisza Enter ...
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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.