Shulou(Shulou.com)06/02 Report--

The format of the for statement

For var in n1,n2,nn

Do

Instruction 1

Instruction 2

...

Done

Or

For var in item1 item2... ItemN; do command1; command2... Done

Example 1

#! / bin/bash

# use literal strings

For x in centos ubuntu gentoo opnesuse

Do

Echo "$x"

Done

# if the list contains space characters, it must be enclosed in quotation marks

For x in Linux "Gnu Hurd" FreeBSD "Mac OS X"

Do

Echo "$x"

Done

# eval variable reference

For x in ls "df-h"du-sh"

Do

Echo "= = $xboys ="; eval $x

Done

Running result

[root@localhost shell] # sh for1.sh

Centos

Ubuntu

Gentoo

Opnesuse

Linux

Gnu Hurd

FreeBSD

Mac OS X

= ls==

Case2.sh case4.sh for1.sh if-elif.sh liu myshell1.sh

Case3.sh case.sh if-elif-if-else.sh if-if.sh liub qq

= df-hype =

Filesystem Size Used Avail Use% Mounted on

/ dev/mapper/centos-root 27G 5.9G 22G 22% /

Devtmpfs 475M 0 475m 0% / dev

Tmpfs 487m 0 487m 0% / dev/shm

Tmpfs 487m 7.7m 479m 2% / run

Tmpfs 487m 0 487m 0% / sys/fs/cgroup

/ dev/sda1 1014M 133M 882M 14% / boot

Tmpfs 98m 0 98m 0% / run/user/0

= du-sh==

36K.

[root@localhost shell] #

Example 2

! / bin/bash

# using variables

I, 1

Weekdays= "Mon Tue Wed Thu Fri"

For day in $weekdays; do

Echo "Weekday $((iTunes +)): $day"

Done

# the default is a space. If the output is not set, the result is

# Linux

# 'Gnu

# Hur'

# FeeBSD

# 'Mac

# OS

# X'

# Others

# set IFS

IFS=:

OSlist= "Linux:'Gnu Hur':FeeBSD:'Mac OS X'"

For x in $OSlist Others; do

Echo "$x"

Done

Running result

[root@localhost shell] # sh for2.sh

Weekday 1: Mon

Weekday 2: Tue

Weekday 3: Wed

Weekday 4: Thu

Weekday 5: Fri

Linux

'Gnu Hur'

FeeBSD

'Mac OS X'

Others

[root@localhost shell] #

Example 3

#! / bin/bash

# use the location variable $@, in $@ can be omitted

I, 1

For day;do

Echo-n "position parameter $((iTunes +)): $day"

Case $day in

[Mm] on | [Tt] ue | [Ww] ed | [Tt] hu | [Ff] ri)

Echo "(weekday)"

[Ss] at | [Ss] un)

Echo "(weekeno)"

*)

Echo "(Invalid weekday)"

Esac

Done

Output result

[root@zabbix shell] # sh for3.sh mon tue wed thu fri sat sun

Position parameter 1: mon (weekday)

Position parameter 2: tue (weekday)

Position parameter 3: wed (weekday)

Position parameter 4: thu (weekday)

Position parameter 5: fri (weekday)

Position parameter 6: sat (weekeno)

Position parameter 7: sun (weekeno)

Example 4

#! / bin/bash

# use a file name or directory

For frname in *

Do

# replace the lowercase file name with the command and assign it to the variable fn

Fn=$ (echo $frname | tr Amurz Amurz)

# determine whether the newly produced file name is the same as the original name, and change it to lowercase if different

If [[$frname! = $fn]]; then mv $frname $fn;fi

# [[$frname! = $fn]] & & mv $frname $fn

# [[$frname = = $fn]] | | mv $frname $fn

Done

Running result

[root@zabbix shell] # touch ABC

[root@zabbix shell] # mkdir qwe

[root@zabbix shell] # sh for4.sh

[root@zabbix shell] # ll

Total dosage 8

-rw-r--r-- 1 root root 0 August 26 15:23 abc

-rw-r--r-- 1 root root 330 August 26 15:11 for3.sh

-rw-r--r-- 1 root root 218 August 26 15:23 for4.sh

Drwxr-xr-x 2 root root 6 August 26 15:23 qwe

Example 5

#! / bin/bash

For i in * .zip

Do

# removing the tail is the .zip section

J = "${i%.zip}"; mkdir "$j" & & unzip-d "$j"$I"

Echo $j

# j = "${i%.zip}"

# echo $j

Done

Execution result

[root@zabbix shell] # sh for5.sh

Archive: adf.zip

Extracting: adf/abc

Inflating: adf/for3.sh

Inflating: adf/for4.sh

Extracting: adf/qq.zip

Creating: adf/qwe/

Extracting: adf/we.zip

Adf

Archive: qq.zip

Extracting: qq/abc

Inflating: qq/for3.sh

Inflating: qq/for4.sh

Creating: qq/qwe/

Extracting: qq/we.zip

QQ

Archive: we.zip

Extracting: we/abc

Inflating: we/for3.sh

Inflating: we/for4.sh

Creating: we/qwe/

We

Example 6

! / bin/bash

# use the execution result of the command as a list

I, 1

For usrname in awk-F:'{print $1}'/ etc/passwd

Do

Echo "Username $((iTunes +)): $usrname"

Done

Echo "* *"

For line in $(cat / etc/yum.conf | egrep-v "^ / | ^ #")

Do

Echo "$line"

Done

Echo "seq Generation sequence"

For suffix in $(seq 5)

Do

Echo "192.168.1.$ {suffix}"

Done

Echo "* *"

For f in $(ls / var/); do

Echo $f

Done

Execution result

Username 10: operator

Username 11: games

Username 12: ftp

Username 13: nobody

Username 14: systemd-network

Username 15: dbus

Username 16: polkitd

Username 17: sshd

Username 18: postfix

Username 19: chrony

Username 20: www

Username 21: mysql

Username 22: saslauth

Username 23: zabbix

Username 24: grafana

Username 25: ntp

[main]

Cachedir=/var/cache/yum/$basearch/$releasever

Keepcache=0

Debuglevel=2

Logfile=/var/log/yum.log

Exactarch=1

Obsoletes=1

Gpgcheck=1

Plugins=1

Installonly_limit=5

Bugtracker_url= http://bugs.centos.org/set_project.php?project_id=23&ref=http://bugs.centos.org/bug_repo

Rt_page.php?category=yum

Distroverpkg=centos-release

192.168.1.1

192.168.1.2

192.168.1.3

192.168.1.4

192.168.1.5

Adm

Cache

Crash

Db

Empty

Games

Gopher

Example 7

#! / bin/bash

# judging host

For host in cat / etc/hosts

Do

If ping-C1-w2 $host & > / dev/null

Then

Echo "Host (${host}) is active."

Else

Echo "Host (${host}) is down."

Fi

Done

Execution result

Root@zabbix shell] # sh for7.sh

Host (127.0.0.1) is active.

Host (localhost) is active.

Example 8

#! / bin/bash

# use numeric values

Myip= "192.168.0"

For num in {1..5}

Do

Echo "IPAddr $num: $myip.$num"

Done

# step size

For num in {1..10..2}

Do

Echo "Number: $num"

Done

Execution result

[root@zabbix shell] # sh for8.sh

IPAddr 1: 192.168.0.1

IPAddr 2: 192.168.0.2

IPAddr 3: 192.168.0.3

IPAddr 4: 192.168.0.4

IPAddr 5: 192.168.0.5

Number: 1

Number: 3

Number: 5

Number: 7

Number: 9

Example 9

#! / bin/bash

For x in {1..5}

Do

Useradd user$ {x}

# stdin is to receive the string after echo as the password. Stdin is a non-exchangeable direct incoming password

# passwd defaults to using the terminal as standard input. Plus-- stdin can be used as standard input.

Echo "centos" | passwd-- stdin user$ {x}

# user first login to change password; chage password invalidation command-d time of last change

Chage-d 0 user$ {x}

Done

Execution result

[root@localhost shell] # sh for3.sh

Changing password for user user1.

Passwd: all authentication tokens updated successfully.

Changing password for user user2.

Passwd: all authentication tokens updated successfully.

Changing password for user user3.

Passwd: all authentication tokens updated successfully.

Changing password for user user4.

Passwd: all authentication tokens updated successfully.

Changing password for user user5.

Passwd: all authentication tokens updated successfully.

[root@localhost shell] # ls / home/

User1 user2 user3 user4 user5

Reopen a terminal with a new user such as: user1

WARNING: Your password has expired.

You must change your password now and login again!

Changing password for user user1.

Changing password for user1.

(current) UNIX password:

Example 10

! / bin/bash

# for nesting

For i in 0 1terdo

For suffix in {1..5}

Do

Ip=192.168.$i.$ {suffix}

If ping-C1-w2 $ip & > / dev/null

Then

Echo "$ip is active."

Else

Echo "Host ($ip) is down."

Fi

Done

Done

Execution result

[root@localhost shell] # sh for4.sh

Host (192.168.0.1) is down.

Host (192.168.0.2) is down.

Host (192.168.0.3) is down.

Host (192.168.0.4) is down.

Host (192.168.0.5) is down.

Host (192.168.1.1) is down.

Host (192.168.1.2) is down.

Host (192.168.1.3) is down.

Host (192.168.1.4) is down.

Host (192.168.1.5) is down.

Example 11

#! / bin/bash

# C language mode

For ((iSuppli)

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