[Print field names along their indexes from tabular data] Most useful for big log files #csv #awk

awk.sh

awk '(NR==1) {for (i=1;i<=NF;i++) print i ": " $i}' <data.csv
# 1: date
# 2: time
# 3: x-edge-location
# 4: sc-bytes
# 5: c-ip
# 6: cs-method
# 7: cs(Host)
# ...

# print date, time and ip

awk 'NR > 1 { OFS=" | "; print $1,$2,$5 }' <data.csv
# 2019-12-04 | 21:02:31 | 192.0.2.100
# 2019-12-04 | 21:02:31 | 192.0.2.100
# ...