Linux Command Learning 1 (awk, grep), awkgrep

Linux Command Learning 1 (awk, grep), awkgrep

1. Write AWK internal code (for better understanding)

BEGIN{size=0}{    if($5>4096){    size=size+$5;    printf("%-10i%s\n",$5,$9)}}END{print "size is",size/1024/1024}

2. Remove the carriage return and add other parts.

ls -l|awk 'BEGIN{size=0}{if($5>4096){size=size+$5;printf("%-10i%s\n",$5,$9)}}END{print "size is",size/1024/1024}'

Objective: To view the files larger than 4 kb in the current directory and add the files to obtain the total size.

3. view files in the current directory larger than 4 kb

ls -l|awk 'if($5>4096){printf("%-10i%s\n",$5,$9)}'

4. AWK common parameter-F (which indicates what is a separator)

grep 'nologin$' /etc/passwd|awk -F ':' '{print $1}'

Objective: To view nologin users

Grep displays the rows ending with nologin. AWK queries the information of the first column separated ":".

5. Common grep Parameters

-C: print the number of rows that meet the requirements (and count the number of rows that meet the requirements)
-I: case insensitive
-N: print the row that meets the requirements and display the row number.
-V: Print B on the contrary (and do not contain the content that meets the requirements)

grep -c 'nologin$' /etc/passwd

Objective: to query the number of nologin users

grep -v 'nologin$' /etc/passwd

Purpose: To query non-nologin users