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SC3056

Vidar Holen edited this page 2020-09-01 17:38:20 -07:00

Table of Contents

• In POSIX sh, name matching prefixes are undefined.
• Problematic code:
• Correct code:
• Rationale:
• Exceptions:
• Related resources:

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!

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