Search notes:

awk examples

number of record of current file ($FNR)

output field separator ($OFS)

awk example: print range

current filename ($FILENAME)

record seperator ($RS)

output record seperator ($ORS)

number of record ($NR)

skip-first-n-lines

number of fields in record ($NF)

field-seperator ($F)

calculate total file size (sum) in a directory