AWK

• Count number of lines in a file

  $ awk 'END { print NR }' <filename>
  

• Grep a pattern in line

  $ echo "Abc123" | awk 'BEGIN {
          regex="[0-9]+"
          }
  {
          if (match($1, regex)) {
                  pattern = substr($1, RSTART, RLENGTH)
          }
          print pattern
  }'
  

• Ignore case in matching string like `grep -i`

  $ echo "caseless" | awk ' BEGIN { IGNORECASE=1; } /CASELESS/ { print }'
  

• Skip first and last column

  # awk '{$1="";$NF="";print}' <filename>