Initial revision of the oldest trick in the book

rm/are_you_sure.md

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+# Are You Sure?
+
+This might be the oldest trick I learned when I started using `rm` and `mv` on the command line on Linux ages ago.
+
+The trick is to use the `-i` option to `rm` and `mv` to make sure you are not deleting or moving the wrong files.
+
+```bash
+alias rm='rm -i'
+```
+
+By creating an alias for `rm` you will be prompted for confirmation before deleting files, since the alias will let `rm` be replaced by `rm -i` which prompts for confirmation.
+
+The same pattern can be used for other commands and simple as it is it can be a lifesaver.