Awk notes
      1 Remove repeated lines Sometimes we want to remove these repeated lines according to some column(s).
1  awk '!a[$2,$3]++' pushLog.log   Above command will print the unique lines after removing repeated in columns 2 and 3.
For instance, there are some SAC files with same header gcarc, and can use the following command to achieve that.
1  saclst gcarc f *.SAC | sort -k2 -n -r | awk '!