SC2313 – ShellCheck Wiki

Quote array indices to avoid them expanding as globs.

Problematic code:

read -r foo[index]

Correct code:

read -r "foo[index]"

Rationale:

ShellCheck found an array element passed to read, where the [] was not quoted. This means the array index [index] will be treated as a glob range, and the word may be replaced or trigger failglob.

In the problematic example, having a directory named food will cause the command to become read -r food instead, since food matches the glob foo[index]. The result is assigning a value to the wrong variable.

Quote or escape the pattern as shown to ensure it always reads into the array foo at index index.

Exceptions:

None.

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