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+## Use || instead of '-o' between test commands.
+
+And variations, like "Use `&&` instead of `and`".
+
+### Problematic code:
+
+```sh
+if [ "$1" = "-v" ] -o [ -n "$VERBOSE" ]
+then
+  echo "Verbose log"
+fi
+```
+
+### Correct code:
+
+```sh
+if [ "$1" = "-v" ] || [ -n "$VERBOSE" ]
+then
+  echo "Verbose log"
+fi
+```
+### Rationale:
+
+You have a `[ .. ]` or `[[ .. ]]` test expression followed by `-o`/`-a` (or by Python-style `or`/`and`).
+
+`-o` and `-a` work *inside* `[ .. ]`, but they do not work *between* them. The Python operators `or` and `and` are never recognized in Bash.
+
+To join two separate test expressions, instead use `||` for "logical OR", or `&&` for "logical AND".
+
+### Exceptions:
+
+None
+
+### Related resources:
+
+* Help by adding links to BashFAQ, StackOverflow, man pages, POSIX, etc!
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