August 2012
Intermediate to advanced
624 pages
17h 11m
Polish
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19.6. Brak cudzysłowów w operacjach przypisania wywołuje błędy „command not found”
Problem
Przygotowany skrypt przypisuje pewne wartości zmiennej, ale podczas wykonywania kodu na ekranie jest wyświetlany komunikat command not found.
$ cat błąd1.sh #!/bin/bash - # typowy błąd: # X=$Y $Z # to nie to samo co: # X="$X $Z" # OPT1=-l OPT2=-h ALLOPT=$OPT1 $OPT2 ls $ALLOPT . $ $ ./błąd1.sh ./błąd1.sh: line 9: -h: command not found błąd1.sh drugi.sh pierwszy.sh $
Rozwiązanie
Wyrażenie zapisane po prawej stronie operatora przypisania (w instrukcji przypisania wartości zmiennej $ALLOPT) musi być otoczone znakami cudzysłowu. Polecenie zapisane jako:
ALLOPT=$OPT1 $OPT2
musi zostać zastąpione kodem:
ALLOPT="$OPT1 OPT2"
Analiza
Przyczyną powstałego problemu jest znak ...
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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.
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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.