Created SC2227 (markdown)

SC2227.md

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+## Redirection applies to the find command itself. Rewrite to work per action (or move to end).
+
+### Problematic code:
+
+```sh
+find . -name '*.ppm' -exec pnmtopng {} > {}.png \;
+```
+
+### Correct code:
+
+```sh
+find . -name '*.ppm' -exec sh -c 'pnmtopng "$1" > "$1.png"' _ {} \;
+```
+### Rationale:
+
+ShellCheck detected a `find` command with a redirection in the middle.
+
+This redirection may have been intended to apply only to a specific action like `-exec` or `-print`, but it does in fact apply to the entire `find` command:
+
+    # This command
+    find . -name '*.ppm' -exec pnmtopng {} > {}.png \;
+
+    # Is the same as this
+    {
+       find . -name '*.ppm' -exec pnmtopng {} \;
+    } > {}.png 
+
+To perform a redirection per action, rewrite it with e.g. `-exec sh -c '...' _ {} \;` 
+
+If the redirection is something like `> /dev/null` where you don't mind it applying to the whole `find` and not individual results, move the redirection to the end of command:
+
+    find . -exec foo {} > /dev/null \;     # Ambiguous syntax. Is it per -exec or not?
+    find . -exec foo {} \;  > /dev/null    # Identical command with clear intent.
+
+### Exceptions:
+
+None
+
+### Related resources:
+
+* Help by adding links to BashFAQ, StackOverflow, man pages, POSIX, etc!