diff --git a/SC2299.md b/SC2299.md new file mode 100644 index 0000000..7024a42 --- /dev/null +++ b/SC2299.md @@ -0,0 +1,32 @@ +## Parameter expansions can't be nested. Use temporary variables. + +### Problematic code: + +```sh +path="/path/to/MyFile.mp3" +echo "Playing ${${path##*/}%.*}" # Expect: Playing MyFile +``` + +### Correct code: + +```sh +path="/path/to/MyFile.mp3" +tmp=${path##*/} +echo "Playing ${tmp%.*}" +``` + +### Rationale: + +ShellCheck found what appears to be a nested parameter expansion. In the example, it was hoping to combine `${var##*/}` to strip the directory and `${var%.*}` to strip the extension. + +Parameter expansions can't be nested. Use temporary variables instead, so that each parameter expansion only does a single operation. + +Alternatively, if the goal is to dynamically generate and expand a variable name, see [[SC2082]]. + +### Exceptions: + +None + +### Related resources: + +* Help by adding links to BashFAQ, StackOverflow, man pages, POSIX, etc! \ No newline at end of file