Simple to use awk

1.awk format

awk [Cutting symbol] '[/ pattern /] Function statement' [filename] 

2. The output of a corresponding column 

All $ 0, $ 1 the first column, the second column ...... $ 2

awk -F: '{print $1}' /etc/passw

3 corresponding to the output line

awk  -F:  'NR==2{print "filename: "FILENAME, $0}' /etc/passwd

awk -F: 'NR==2{print "filename: "$1}' /etc/passwd

4. Specify delimiter -F

awk    -F  :      'NR==2{print "filename: "FILENAME, $0}' /etc/passwd

Multi separator awk -F "[:, /]" 'NR == 2 {print "filename:" FILENAME, $ 0}' / etc / passwd

The use of a plurality of spaces of regular filter

ifconfig |grep eth* | awk -F '[ ]+' '{print $1}'

6.awk Programming

Worth the number of files in the statistics, and the average

awk 'BEGIN{count=0;}{split($0,a,"\t");for(i in a){count+=a[i];times+=1;}}END{print times,count,count/times}' log_20191022194429