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Vidar Holen edited this page Sep 2, 2020 · 1 revision

In POSIX sh, name matching prefixes are undefined.

(or "In dash, ... are not supported." when using dash)

Problematic code:

#!/bin/sh
echo "${!ANDROID_*}"

Correct code:

The easiest solution is to switch to a shell that does support name matching prefixes, like bash:

#!/bin/bash
echo "${!ANDROID_*}"

Alternatively, extract the data you want from env or set

Rationale:

Using ${!name*} to find all variable names with a given prefix is a bash and ksh extension that dash and POSIX sh does not support.

Exceptions:

If you only intend to target shells that supports this feature, you can change the shebang to a shell that guarantees support, or ignore this warning.

You can use # shellcheck disable=SC3000-SC4000 to ignore all such compatibility warnings.

Related resources:

  • Help by adding links to BashFAQ, StackOverflow, man pages, POSIX, etc!

ShellCheck

Each individual ShellCheck warning has its own wiki page like S001. Use GitHub "Pages" feature above to find a specific one, or see Checks.

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