Does Bash have a way to access arrays similar to Zsh, something like
$ foo=(dog cat mouse)
$ echo $foo[1]
cat
instead of
$ echo ${foo[1]}
perhaps using some shopt setting?
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1Nope. Note that in zsh. $foo[1] is dog, not cat (unless you're in sh or ksh emulation).– Stéphane ChazelasDec 3, 2012 at 23:37
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1 Answer
No. If you want a shell with a lot of options that let you tune the syntax, use zsh. Bash is conservative and does not tend to implement features that would break existing POSIX or ksh scripts. Bash and ksh maintain compatibility with historical shells where $foo[1] is perfectly valid and expands to dog[1] (or dog1 if there is a file by that name).
answered Dec 3, 2012 at 23:45
Gilles 'SO- stop being evil'Gilles 'SO- stop being evil'
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To be fair to zsh, when in sh/bash/ksh mode (as in when called as "sh"/"ksh"/"bash"), that is when compatibility matters, zsh behaves like bash in this regard. Dec 3, 2012 at 23:50
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@StephaneChazelas What I meant is that zsh has a mode where it does things its own way (plus a squillion options), in addition to its POSIX-like, ksh-like and csh-like settings. Bash hardly strays much from POSIX-like and ksh-like. Dec 4, 2012 at 0:02
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bashis definitively implementing a lot of features, sometimes copied fromzsh, but at its own pace. And bash features can break POSIX standard: this is called a bashism, it is very frequent since Ubuntu link/bin/shtodashand it is even a regular entry in the wiktionary !– calandoaMay 3, 2019 at 9:39 -
@calandoa Most places where bash is incompatible from POSIX date back from the 20th century and are preserved for backward compatibility. Most of these features are easy to avoid in scripts, so scripts written for POSIX sh almost always work in bash. A bashism is where bash extends POSIX, so scripts that rely on these features don't work with other sh implementations. May 3, 2019 at 9:55
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@Gilles The question is not about zsh or bash conformity with POSIX syntax, it is about a new feature present in zsh and not (yet?) in bash. And btw, both zsh and bash have POSIX compatibility mode, and most non POSIX features from bash are recent: the intial version's goal was to provide a GPL version of Bourne's shell, the following versions are providing new features handy for users.– calandoaMay 3, 2019 at 11:01