let count++ gives a warning suggesting (( count++ )) instead. The deleted "Equivalently" code was _not_ equivalent and it didn't work because count was modified in a subshell (as shellcheck itself points out)

SC2044.md

@@ -5,7 +5,7 @@
 ```sh
 for file in $(find mydir -mtime -7 -name '*.mp3')
 do
-  let count++
+  (( count++ ))
   echo "Playing file no. $count"
   play "$file"
 done
@@ -23,25 +23,13 @@ The most general fix (that requires the least amount of thinking to apply) is ha
 ```sh
 while IFS= read -r -d '' file
 do
-  let count++
+  (( count++ ))
   echo "Playing file no. $count"
   play "$file"
 done <   <(find mydir -mtime -7 -name '*.mp3' -print0)
 echo "Played $count files"
 ```
 
-> Equivalently:
-> 
-> ```sh
-> find mydir -mtime -7 -name '*.mp3' -print0 | while IFS= read -r -d '' file
-> do
->   let count++
->   echo "Playing file no. $count"
->   play "$file"
-> done
-> echo "Played $count files"
-> ```
-
 In usage it's very similar to the `for` loop: it gets its output from a `find` statement, it executes a shell script body, it allows updating/aggregating variables, and the variables are available when the loop ends.
 
 It requires Bash, and works with GNU, Busybox, OS X, FreeBSD and OpenBSD find, but not POSIX find.
@@ -54,7 +42,7 @@ If you don't need `find` logic like `-mtime -7` and just use it to match globs r
 shopt -s globstar nullglob
 for file in mydir/**/*.mp3
 do
-  let count++
+  (( count++ ))
   echo "Playing file no. $count"
   play "$file"
 done