The filenames for normal future contracts typically include a symbol, the numerical delivery month and the delivery year. An ASCII file might be listed in your portfolio as:
ASCII comma w/century daily file -->LC_1997M.CSV
This would follow a header identifying the commodity. The actual filename (at right) shows the symbol (LC for Live Cattle with an underscore padding the three-character field), the delivery year (1997), a single-digit delivery month code (M for June) and a three-character file extension as selected by the user. Alternate presentations can include a code identifying the exchange and other options. A numerical delivery month code 1 - 12 can replace the alphabetic exchange-based one shown here:
F - Jan G - Feb H - Mar J - Apr K - May M - Jun
N - Jul Q - Aug U - Sep V - Oct X - Nov Z - Dec