Awk's use case

How to use

awk [-F Separator] ' handling of operations ' is the file name to be processed

It can be separated by a space without a separator.

Three ways to execute awk

1. Command mode

2.Shell scripting #!/bin/awk on the first line

3. Insert all awk commands into a single file using the awk - F awk command file with the processing file

A few simple examples

1. Get the most recently logged in user name simple print

Last - N 5 | awk ' {print '} '

2. Get/etc/passwd account Specify the delimiter

$ indicates that all the domains , $ represents the first domain , $n represents the first N a domain

CAT/ETC/PASSWD |awk-f ': ' {print $} '

can also

Awk-f ': ' {print $} '/etc/passwd

Print multiple columns

awk-f ': ' {print $ \ t ' $7} '/etc/passwd

3. Use Begin end  

Example 1

CAT/ETC/PASSWD |awk-f ': ' BEGIN {print ' Name,shell '} {print $ ', ' $7} END {print ' Blue,/bin/nosh '} '

Example 2

Awk-f ":" ' begin{count=0;} {name[count]=$1;count++} End{for (i=0;i<count;i++) print I,name[i]} '/etc/passwd

4. Using the regular

Example 1 View all columns that contain ysql

Awk-f ":" ' begin{count=0;} /ysql/{name[count]=$1;count++}end{for (i=0;i<count;i++) print I,name[i]} '/etc/passwd

Example 2 View all columns beginning with Ysql

Awk-f ":" ' begin{count=0;} /^ysql/{name[count]=$1;count++}end{for (i=0;i<count;i++) print I,name[i]} '/etc/passwd

Example 3 View all columns ending in Ysql

Awk-f ":" ' begin{count=0;} /ysql$/{name[count]=$1;count++}end{for (i=0;i<count;i++) print I,name[i]} '/etc/passwd

Note that the regular must be placed behind the begin

Awk's use case