Problem with Node.js and child_process.exec arguments

On the command line, if I run

echo -n "foo" | openssl aes-128-cbc -k "key" -base64 -e

(the -n flag prevents echo from adding a newline to the end of its output), I get

U2FsdGVkX1+nMW5I4eZSasPKfsUuCpbFsnn56ngEdec=

But when I run

exec = require('child_process').exec;
exec('echo -n "foo" | o开发者_如何转开发penssl aes-128-cbc -k "key" -base64 -e', callback);

the callback gets the output

U2FsdGVkX1/CARBiGos0x9ALNhFqcIaFvZ9EUvVBxuc=

Why is it different? Decrypt it, and you'll get the string

-n foo

So somehow, exec encoded -n "foo" into "-n foo" (under Node 0.4.2).

Here's the weirdest part: I don't get this problem when I run my code directly from TextMate (via jashkenas' CoffeeScript bundle). At first I thought it was a path issue, but it isn't (making PATH identical in the two environments had no effect). Perhaps it's because one environment is a TTY and one isn't.

Are other folks aware of this inconsistency? Is this a Node bug, or am I ignoring something? I'm guessing that my problems will go away if I use the lower-level spawn instead of exec.

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Perhaps your /bin/echo doesn't respect -n? echo is frequently a shell builtin, and that one may respect -n. You may wish to use printf(1) instead, it is more portable.