awk

Print all but the first column

awk '{$1="";$0=substr($0,2)}1'

• $1="" - empty the first field
• $0=substr($0,2) - start the whole line at the second position and ignore the space at the first position
• 1 - awk evaluates this as true and the default action is to print the line

Print all but the last column

awk '{$NF=""; NF--; print}'

Find the sum of the 5th column of numbers from stdin

awk '{total+=$5} END {print total}'

Find the average of the 8th column of numbers from stdin

awk '{sum+=$8; ++n} END {print sum/n}'

Print the number of columns

awk '{print NF}'

Calculate 80% of 3rd column

awk '{print $3 * 0.8}'