From 543541b589e067f2d867cfa8cf2b4c5d36cc9f9c Mon Sep 17 00:00:00 2001
From: Vidar Holen <vidar@vidarholen.net>
Date: Wed, 2 Nov 2022 21:09:04 -0700
Subject: [PATCH] Created SC3042 (markdown)

---
 SC3042.md | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 SC3042.md

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+## In POSIX sh, set flag `--default` is undefined
+
+(or any other option)
+
+### Problematic code:
+
+```sh
+#!/bin/ksh
+set --default
+```
+
+### Correct code:
+
+Switch to a shell that supports these options, such as Ksh:
+
+```sh
+#!/bin/ksh
+set --default
+```
+
+### Rationale:
+
+Your script uses a shell feature not supported by the shebang. Either rewrite the script to be portable, or change the shebang to explicitly require a shell like Ksh.
+
+Most shell specific `set` flags are hard to emulate in POSIX, so use your best judgement as to whether you can make do without them, or if you should require a shell that supports them.
+
+### Exceptions:
+
+None
+
+### Related resources:
+
+* Help by adding links to BashFAQ, StackOverflow, man pages, POSIX, etc!
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