Links
See my Wikipedia contributions and techie tidbits (plus cat pics) on Twitter.
xy
ASCII line plotter, takes a CSV on the command line (or stdin) and emits a graph -- repo/example website
tracehost
Network mapper using bash and GraphViz -- repo/website
Have A Nice Day Trader
Trading strategy backtester -- repo/website
tradeR
Currency analysis in R -- repo/website
BIGO
Exploring Big 'O' programatically -- website
Spectrum
Command line audio analysis -- repo
DFT
Discrete Fourier transforms -- repo