Linux Common basic commands: The-awk mode usage of the Three Musketeers command (2)

1, regular mode, filter out users using/bin/bash in/etc/passwd

[Email protected]:~/linux/awk$awk-V fs=":" 'begin{printf "%-10s%-10s%-10s\n", "User name", "User ID", "bash"}/\/bin\/bash$/{printf "%-10s\t%-10s\t%-10s\n", $1,$3, $NF }'/etc/passwdUser name User ID bash root0/bin/Bash GHOSTWU +/bin/Bash Guest-iilhaz999/bin/bash [email protected]:~/linux/awk$grep "/bin/bash"/etc/passwdroot:x:0:0: root:/root:/bin/bashghostwu:x: +: +: GHOSTWU,,,:/home/ghostwu:/bin/bashguest-IILHAZ:X:999:999: Guest:/tmp/guest-iilhaz:/bin/bash

> Remove \bin\bash end of line from/etc/passwd

> After the qualifying rows are found, separate the line text with the ":" Sign.

> Take out the required segments, format the output

> formatting text with begin mode and printf

2, extract/etc/passwd, more than 7 letters account, use {n,m} number of matches, need to add--re-interval

[Email protected]:~/linux/awk$awk--re-interval-v fs=":" 'begin{printf "%-10s%-10s\n", "username", "id"}/^\w{7,}/{printf "%-10s\t%-10s\n", $1,$3}'/etc/passwdUser nameIDsystemd-timesync -systemd-network101systemd-resolve102systemd-bus-proxy103Messagebus106LIGHTDM108Whoopsie109DNSMASQ theKernoops theGHOSTWU +   

3, row range matching mode

Format: awk '/regular 1/,/regular 2/{action} ' FILE

Matches all rows that ghostwu the first occurrence of the row, to the Zhanzhao first occurrence of the row, "Note: is the first occurrence as a matching criterion"

[Email protected]:~/linux/awk$Cat-N ghostwu.txt1Ghostwu - Mans     2Zhangsan A     3Lisi4Ghostwu - Mans     5Zhanzhao + Mans     6Peter - Mans     7Zhanzhao - Mans[email protected]:~/linux/awk$awk '/ghostwu/,/zhanzhao/{print}'ghostwu.txt GHOSTWU - MansZhangsan ALISIGHOSTWU - MansZhanzhao + Mans

Of course, the above example can also be used before the built-in variable nr, the relationship expression pattern implementation easier

[Email protected]:~/linux/awkawk'nr>=1 && nr<=5{print}'  man     + Mans

4, relational operators are used in conjunction with regular matches to match the network segment that satisfies the format

[Email protected]:~/linux/awk$Cathost.txt name IP address host1192.168.1.1Host2192.177.81.1Host310.0.0.5Host4192.168.3.98Host5192.168.3.98Host6192.168.9.254[email protected]:~/linux/awk$awk--re-interval'$2~/192\.168\. [0-9] {1,3}\. [0-9] {1,3}/{print}'host.txt host1192.168.1.1Host4192.168.3.98Host5192.168.3.98Host6192.168.9.254

$: The 2nd column, followed by the ~ indicates that the second column matches the result of the regular expression followed by the true, execute action, here is the print current line {print}, if added! is to take the counter

[Email protected]:~/linux/awkawk'$2!~/192\.168\.[ 0-9]{1,3}\. [0-9] {1,3}/{print}'  host.txt name    IP address host2    192.177.  81.1host3    10.0.  0.5

Relational operators	Meaning	Usage examples
<	Less than	X < y
<=	Less than or equal	X <= y
==	Equals	x = = y
!=	Not equal to	X! = y
>=	Greater than or equal	X >= y
>	Greater than	X > Y
~	Matches the corresponding regular match is true	x ~/Regular/
!~	True if the corresponding regular is not matched	x!~/Regular/

Pattern Summary:

> Empty mode

> Relational operation mode

> Regular mode

> Row Range Mode

>begin/end mode

Linux Common basic commands: The-awk mode usage of the Three Musketeers command (2)