SC3043

In POSIX sh, local is undefined.

Problematic code:

myfunc() {
  local i=0
  ..
}

Correct code:

In POSIX sh, you can adopt some convention to avoid accidentally overwriting variables names, e.g. prefixing with the function name:

myfunc() {
  _myfunc_i=0
  ..
}

You can also unset the variable at the end of the function:¹

myfunc() {
  i=0
  ..
  unset i
}

You can also use POSIX’s set +a or set +o allexport which prevents the “export attribute” from being “set for each variable to which an assignment is performed”:²

myfunc() {
  set +a || set +o allexport # either will work – don’t use both.
  i=0
  ..
  set -a || set -o allexport # optionally undo `set` modifications
}

Rationale:

local is supported in many shells, including bash, ksh, dash, and BusyBox ash. However, strictly speaking, it's not POSIX.

Exceptions:

Since quite a lot of real world shells support this feature, you may decide to ignore the warning.

Related resources:

1. Shell Command Language § unset (archived)
2. Shell Command Language § Description (archived)

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