Problem
When running mongod/mongo/mongos, you got message like this:
mongod: error while loading shared libraries: libmozjs.so: cannot open shared object file: No such file or directory

Solution
Make sure you have xulrunner-dev installed:
sudo apt-get install xulrunner-dev

then find libmozjs on your filesystem:
sudo locate libmozjs

in lucid, it’s supposed to locate at:
/usr/lib/xulrunner-1.9.2.6/libmozjs.so

(and some other directories, such as firefox / thunderbird / seamonkey)

Just create a symbol link:
sudo ln -s /usr/lib/xulrunner-1.9.2.6/libmozjs.so /usr/lib/

try to restart mongodb:
sudo service mongodb start

take a look at process list:
ps aux | grep mongo

it works.

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