From 1c2f04e5af69bfe67e3bc2d97add9a8deb16966c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lawrence=20Vel=C3=A1zquez?= <larry.velazquez@gmail.com>
Date: Sun, 20 Mar 2022 20:59:50 -0400
Subject: [PATCH] Generalize "Rationale" section; move `pipefail`-specific info
 to a separate section; link to POSIX spec for `set`

---
 SC3040.md | 34 +++++++++++++++++-----------------
 1 file changed, 17 insertions(+), 17 deletions(-)

diff --git a/SC3040.md b/SC3040.md
index 5c80d86..f0c72f9 100644
--- a/SC3040.md
+++ b/SC3040.md
@@ -1,12 +1,20 @@
-## In POSIX sh, set option <option> is undefined.
+## In POSIX sh, set option *[name]* is undefined.
 
-This applies to any POSIX code: `set -o <option>` is **undefined**.
+The value *[name]* may be anything other than `allexport`, `errexit`, `ignoreeof`, `monitor`, `noclobber`, `noexec`, `noglob`, `nolog`, `notify` , `nounset`, `verbose`, `vi`, and `xtrace`.
 
-Examples follow:
+<!-- https://github.com/koalaman/shellcheck/blob/3b6972fbf14d98dded7ebfc65af6b73724be4efa/src/ShellCheck/Checks/ShellSupport.hs#L334-L337 -->
 
-----
+### Rationale:
 
-### Problematic code:
+In a script declared to run with `sh` or `dash`, ShellCheck found `set -o` used with an option that is not defined by POSIX. The option may not be supported by these shells.
+
+### Exceptions:
+
+If the script has already inspected the current shell and determined the option is available, you can [[ignore]] this message.
+
+### `pipefail`
+
+#### Problematic code:
 
 ```sh
 #!/bin/sh
@@ -17,7 +25,7 @@ then
 fi
 ```
 
-### Correct code:
+#### Correct code:
 
 ```sh
 fail="$(mktemp)"
@@ -30,22 +38,14 @@ fi
 rm "$fail"
 ```
 
-or switch to a shell that supports pipefail, such as Bash.
-
-### Rationale:
-
-ShellCheck found `set -o pipefail` in a script declare to run with `sh` or `dash`. This feature may not be supported on these shells.
-
-As an alternative, each stage in the pipeline such as `cmd1` can be rewritten as `{ cmd1 || echo > file; }` which will behave as before but now also write the exit code into `file` if the command fails.
+Each stage in the pipeline such as `cmd1` can be rewritten as `{ cmd1 || echo > file; }` which will behave as before but now also write the exit code into `file` if the command fails.
 
 If the file has been written to when the pipeline is done, it means one of the commands failed. This is demonstrated in the correct example.
 
 This can obviously be extended with e.g. `echo "cmd1=$?" >> file` if the particular exit codes for particular commands are desired.
 
-### Exceptions:
-
-If the script has already inspected the current shell and determined the option is available, you can [[ignore]] this message.
+Alternatively, switch to a shell that supports `pipefail`, such as Bash.
 
 ### Related resources:
 
-* Help by adding links to BashFAQ, StackOverflow, man pages, POSIX, etc!
\ No newline at end of file
+* [POSIX.1-2017 - Shell Command Language - `set`](https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#set)
\ No newline at end of file