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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 SC1000. Use GitHub Wiki's "Pages" feature above to find a specific one, or see Checks.

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