From 28e8f87bce17aec2a81524659ce1e81df4f3995d Mon Sep 17 00:00:00 2001 From: Vidar Holen Date: Wed, 2 Nov 2022 21:16:26 -0700 Subject: [PATCH] Created SC3052 (markdown) --- SC3052.md | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) create mode 100644 SC3052.md diff --git a/SC3052.md b/SC3052.md new file mode 100644 index 0000000..471d24f --- /dev/null +++ b/SC3052.md @@ -0,0 +1,30 @@ +## In POSIX sh, arithmetic base conversion is undefined + + +### Problematic code: + +```sh +#!/bin/sh +echo "Hex $1 is decimal $((16#$1))" +``` + +### Correct code: + +```sh +#!/bin/sh +echo "Hex $1 is decimal $(echo "ibase=16; $1" | bc)" +``` + +### Rationale: + +Your script uses a shell feature not supported by the shebang. Either rewrite the script to be portable, or change the shebang to explicitly require a shell like Bash. + +In this case, using radix specifiers in arithmetic contexts, such as `$((16#DEADBEEF))` is not portable. `bc` ibase/obase can be used instead. + +### Exceptions: + +None + +### Related resources: + +* Help by adding links to BashFAQ, StackOverflow, man pages, POSIX, etc! \ No newline at end of file