Question: how to subtract days from a date in unix?
Answer: current date command runs well awk -v t="$(date +%Y-%m-%d)" -F "'" '$1 < t' myname. dat subtract 30 days fails awk -v t="$(date --date="-30days" +%Y-%m-%d)" -F "'" '$1 < t' myname. dat awk command in hp unix subtract 30 days automatically from current date without date illegal option error...