I'm currently using Nim at work as a replacement for some old scripts, mostly for provisioning servers (as part of our Ansible deployment setup). The tools in question preform tasks such as creating MySQL databases and the required tables/relationships and importing initial data and downloading a set of applications from our SVN server, zipping them up (using the zipfiles module) and then deploying them onto the servers.
We've also written some other small utilities in Nim that would have been written in Python or other languages in the past to do tasks such as monitoring data coming in from a serial port and logging that data with timestamps per packet.
