Linux811 YUM；SHELL:if else fi,for

czhc11400756632025-08-12 7:05

vsftpdok

bash 复制代码 
[root@web ~]# vim vsftpdok.sh
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[root@web ~]# cat vsftpdok.sh
rpm -ql vsftpd >/dev/null 2>&1
if [ $? -eq 0 ];then
echo "OK"
else
yum install vsftpd -y
if [ $? -eq 0 ];then
echo "install ok"
else
echo "not install"
fi
fi
[root@web ~]# chmod +x vsftpdok.sh
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[root@web ~]# ./vsftpdok.sh
OK

uname -r

bash 复制代码 
[root@web ~]# cat unameok.sh
a=$(uname -r)
echo $a
if [ $? -eq 0 ];then
main=`echo $a|cut -d "." -f1`
extra=`echo $a|cut -d "." -f2`
echo $main
echo $extra
if [ $main == 2 ]&&[ $extra >= 6 ];then
echo $a
else echo "wrong"
fi
fi
[root@web ~]# ./unameok.sh
3.10.0-1160.el7.x86_64
3
10
wrong

vsftpd port pid

bash 复制代码 
[root@web ~]# cat ftpok.sh
a=$(ss -naltp|grep vsftpd)
if [ $? == 0 ];then
port=`echo $a|cut -d ":" -f4`
realport=`echo $port|cut -c1-2`
pid=`echo $a|cut -d ":" -f8`
realpid=`echo $pid|cut -d "," -f2`
echo "vsftpd.server has been started"
echo "vsftpd listen on:"$realport
echo "vsftpd's process pid is:"$realpid
else
echo "vsftpd not start"
fi
[root@web ~]# ./ftpok.sh
vsftpd.server has been started
vsftpd listen on:21
vsftpd's process pid is:pid=1735
[root@web ~]# ss -naltp |grep vsftpd
LISTEN     0      32        [::]:21                    [::]:*                   users:(("vsftpd",pid=1735,fd=4))

for

bash 复制代码 
[root@web ~]# cat testcfor.sh
for (( i=1;i<=5;i++))
       do
            echo $i
       done

[root@web ~]# chmod +x testcfor.sh
[root@web ~]# ./testcfor.sh
1
2
3
4
5
[root@web ~]# vim testcfor.sh
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[root@web ~]# cat testcfor.sh
for (( i=1;i<=5;i++))
       do
            echo $i
       done
for (( i=1;i<=5;i++))
do
echo $i
done
for ((i=1;i<=10;i+=2))
do
echo $i
done
for ((i=2;i<=10;i+=2))
do
echo $i
done
[root@web ~]# ./testcfor.sh
1
2
3
4
5
1
2
3
4
5
1
3
5
7
9
2
4
6
8
10

奇数和 <100

bash 复制代码 
[root@web ~]# vim sum.sh
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[root@web ~]# cat sum.sh
declare -i sum=0
for (( i=1;i<=100;i+=2 ))
do
sum+=i
done
echo "sum is:"$sum
[root@web ~]# ./sum.sh
sum is:2500

touch

bash 复制代码 
[root@web ~]# vim for51.sh
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[root@web ~]# cat for51.sh
for i in {1..5}
do
test $i -eq 2 && break || touch /tmp/ffile$i
done
echo lllllll
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[root@web ~]# ls /tmp
1.txt                sys-20250804.tar.gz
2.txt                sys-20250805.tar.gz
3.txt                sys-20250806.tar.gz
5.txt                sys-20250807.tar.gz
6.txt                sys-20250810.tar.gz
abc.txt              sys-20250811.tar.gz
dir1                 systemd-private-6f37c267bc534142983b62ad1ab0be9a-bolt.service-LMvltW
dir2                 systemd-private-6f37c267bc534142983b62ad1ab0be9a-chronyd.service-UWJorp
file1                systemd-private-6f37c267bc534142983b62ad1ab0be9a-colord.service-tLvcX3
file2                systemd-private-6f37c267bc534142983b62ad1ab0be9a-cups.service-LjtpWQ
file3.patch          systemd-private-6f37c267bc534142983b62ad1ab0be9a-rtkit-daemon.service-gttbXa
file5                systemd-private-e06954d935da43dd9840443262c2b912-bolt.service-Shxrsd
file6.patch          systemd-private-e06954d935da43dd9840443262c2b912-chronyd.service-NvD4bP
file.patch           systemd-private-e06954d935da43dd9840443262c2b912-colord.service-N0eYTb
passwd               systemd-private-e06954d935da43dd9840443262c2b912-cups.service-xuO8Nz
swapfile             systemd-private-e06954d935da43dd9840443262c2b912-rtkit-daemon.service-BM4Ksb
sys-20250728.tar.gz  vmware-root_1022-2999133054
sys-20250729.tar.gz  vmware-root_1207-3979642956
sys-20250730.tar.gz  vmware-root_1329-4256610699
sys-20250731.tar.gz  vmware-root_845-4021653450
sys-20250801.tar.gz  vmware-root_971-4290232077
sys-20250803.tar.gz

素数判断

bash 复制代码 
[root@web ~]# cat judgeprime.sh
declare -i n
read -p "please input a number:" n
if [ $n -le 1 ];then
echo "n is not a prime number"
exit 0
fi
is_prime=0
for (( i=1;i<=n;i++ ))
do
if [ i != 1 ] && [ i != $n ] && [ $(($n%i == 0)) ];then
is_prime=1
break
fi
done
if [ is_prime == 0 ];then
echo $n " is a prime number "
else
echo $n " is not prime number"
fi

[root@web ~]# ./judgeprime.sh
please input a number:1
n is not a prime number
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[root@web ~]# ./judgeprime.sh
please input a number:5
5  is not prime number

问题

bash 复制代码 
[root@localhost yum.repos.d]# cat local.repo
[local yum]
name = local yum
baseurl = file:///mnt
gpgcheck = 0
enabled =1
[root@localhost yum.repos.d]# yum clean all
已加载插件：fastestmirror
Bad id for repo: local yum, byte =   5
Loading mirror speeds from cached hostfile
There are no enabled repos.
 Run "yum repolist all" to see the repos you have.
 To enable Red Hat Subscription Management repositories:
     subscription-manager repos --enable <repo>
 To enable custom repositories:
     yum-config-manager --enable <repo>
[root@localhost yum.repos.d]#
bash 复制代码 
[root@localhost yum.repos.d]# echo ${a[@]}
LISTEN 0 32 [::]:21 [::]:* users:(("vsftpd",pid=23514,fd=4))
[root@localhost yum.repos.d]# c=("echo ${a[@]}|cut -d ":" -f8")
[root@localhost yum.repos.d]# echo $c
echo LISTEN
[root@localhost yum.repos.d]# echo {c[@]}
{c[@]}
[root@localhost yum.repos.d]# echo ${c[@]}
echo LISTEN 0 32 [::]:21 [::]:* users:(("vsftpd",pid=23514,fd=4))|cut -d : -f8
bash 复制代码 
[root@localhost yum.repos.d]# d=("echo ${a[@]}|cut -d ":" -f6")
[root@localhost yum.repos.d]# echo $d
echo LISTEN
[root@localhost yum.repos.d]# echo ${d[@]}
echo LISTEN 0 32 [::]:21 [::]:* users:(("vsftpd",pid=23514,fd=4))|cut -d : -f6
bash 复制代码 
[root@web ~]# a=("uname -r")
[root@web ~]# echo $a
uname -r
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[root@web ~]# a=(`uname -r`)
[root@web ~]# echo $a
3.10.0-1160.el7.x86_64
[root@web ~]#
bash 复制代码 
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[root@web ~]# echo $hostname

[root@web ~]# echo $(hostname)
web.cn


{}


()





[]



a

bash 复制代码 
[root@web ~]# cat judgeprime.sh
declare -i n
read -p "please input a number:" $n
for i in {1..n}
do
if [ i != 1 ] && [ i != $n ] && [ $n%i == 0 ];then
echo $n" is a prime number " && break
else
fi
done
echo $n"is a prime number"

[root@web ~]# chmod +x judgeprime.sh
[root@web ~]# ./judgeprime.sh
please input a number:2
./judgeprime.sh:行8: 未预期的符号 `fi' 附近有语法错误
./judgeprime.sh:行8: `fi'
bash 复制代码 
[root@web ~]# cat judgeprime.sh
declare -i n
read -p "please input a number:" n
if [ n <= 1 ];then
echo "n is not a prime number"
exit 0
fi
for (( i=1;i<=n;i++ ))
do
if [ i != 1 ] && [ i != $n ] && [ $(($n%i == 0)) ];then
echo $n" is not prime number " && break
fi
done
echo $n"is a prime number"

[root@web ~]# ./judgeprime.sh
please input a number:4
./judgeprime.sh:行3: =: 没有那个文件或目录
4 is not prime number
4is a prime number
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[root@web ~]# ./judgeprime.sh
please input a number:1
./judgeprime.sh:行3: =: 没有那个文件或目录
1 is not prime number
1is a prime number
[root@web ~]#

记录

bash 复制代码 
root@192.168.131.5's password:
    ┌──────────────────────────────────────────────────────────────────────┐
    │                 • MobaXterm Personal Edition v24.3 •                 │
    │               (SSH client, X server and network tools)               │
    │                                                                      │
    │ ⮞ SSH session to root@192.168.131.5                                  │
    │   • Direct SSH      :  ✓                                             │
    │   • SSH compression :  ✓                                             │
    │   • SSH-browser     :  ✓                                             │
    │   • X11-forwarding  :  ✗  (disabled or not supported by server)      │
    │                                                                      │
    │ ⮞ For more info, ctrl+click on help or visit our website.            │
    └──────────────────────────────────────────────────────────────────────┘

Last login: Mon Aug 11 21:09:27 2025
[root@localhost ~]# ls
anaconda-ks.cfg
[root@localhost ~]# cd /etc/yum.repos.d
[root@localhost yum.repos.d]# ls
CentOS-Base.repo       CentOS-fasttrack.repo  CentOS-Vault.repo
CentOS-CR.repo         CentOS-Media.repo      CentOS-x86_64-kernel.repo
CentOS-Debuginfo.repo  CentOS-Sources.repo
[root@localhost yum.repos.d]# tar -zcf repo.tar.gz *.repo
[root@localhost yum.repos.d]# ls
CentOS-Base.repo       CentOS-fasttrack.repo  CentOS-Vault.repo
CentOS-CR.repo         CentOS-Media.repo      CentOS-x86_64-kernel.repo
CentOS-Debuginfo.repo  CentOS-Sources.repo    repo.tar.gz
[root@localhost yum.repos.d]# rm -rf *.repo
[root@localhost yum.repos.d]# ls
repo.tar.gz
[root@localhost yum.repos.d]# lsblk
NAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda               8:0    0   20G  0 disk
├─sda1            8:1    0    1G  0 part /boot
└─sda2            8:2    0   19G  0 part
  ├─centos-root 253:0    0   17G  0 lvm  /
  └─centos-swap 253:1    0    2G  0 lvm  [SWAP]
sr0              11:0    1  4.4G  0 rom
[root@localhost yum.repos.d]# cat /mnt
cat: /mnt: 是一个目录
[root@localhost yum.repos.d]# cd /mnt
[root@localhost mnt]# ls
[root@localhost mnt]# mount -o ro /dev/sr0 /mnt
[root@localhost mnt]# lsblk
NAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda               8:0    0   20G  0 disk
├─sda1            8:1    0    1G  0 part /boot
└─sda2            8:2    0   19G  0 part
  ├─centos-root 253:0    0   17G  0 lvm  /
  └─centos-swap 253:1    0    2G  0 lvm  [SWAP]
sr0              11:0    1  4.4G  0 rom  /mnt
[root@localhost mnt]# chmod +x /etc/rc.local
[root@localhost mnt]# echo "mount -o ro /dev/sr0 /mnt">>/etc/rc.local
[root@localhost mnt]# cat /etc/rc.local
#!/bin/bash
# THIS FILE IS ADDED FOR COMPATIBILITY PURPOSES
#
# It is highly advisable to create own systemd services or udev rules
# to run scripts during boot instead of using this file.
#
# In contrast to previous versions due to parallel execution during boot
# this script will NOT be run after all other services.
#
# Please note that you must run 'chmod +x /etc/rc.d/rc.local' to ensure
# that this script will be executed during boot.

touch /var/lock/subsys/local
mount -o ro /dev/sr0 /mnt
[root@localhost mnt]# cd /etc/yum.repos.d
[root@localhost yum.repos.d]# ls
repo.tar.gz
[root@localhost yum.repos.d]# vim local.repo
-bash: vim: 未找到命令
[root@localhost yum.repos.d]# vi local.repo
[root@localhost yum.repos.d]# cat local.repo
[local yum]
name = local yum
baseurl = file:///mnt
gpgcheck = 0
enabled =1
[root@localhost yum.repos.d]# yum clean all
已加载插件：fastestmirror
Bad id for repo: local yum, byte =   5
Loading mirror speeds from cached hostfile
There are no enabled repos.
 Run "yum repolist all" to see the repos you have.
 To enable Red Hat Subscription Management repositories:
     subscription-manager repos --enable <repo>
 To enable custom repositories:
     yum-config-manager --enable <repo>
[root@localhost yum.repos.d]# vi local.repo
[root@localhost yum.repos.d]# cat local.repo
[local]
name = local yum
baseurl = file:///mnt
gpgcheck = 0
enabled =1
[root@localhost yum.repos.d]# yum clean all
已加载插件：fastestmirror
正在清理软件源： local
Cleaning up list of fastest mirrors
[root@localhost yum.repos.d]# yum makecache
已加载插件：fastestmirror
Determining fastest mirrors
local                                                    | 3.6 kB     00:00
(1/4): local/group_gz                                      | 153 kB   00:00
(2/4): local/primary_db                                    | 3.3 MB   00:00
(3/4): local/filelists_db                                  | 3.3 MB   00:00
(4/4): local/other_db                                      | 1.3 MB   00:00
元数据缓存已建立
[root@localhost yum.repos.d]# yum repolist
已加载插件：fastestmirror
Loading mirror speeds from cached hostfile
源标识                              源名称                                 状态
local                               local yum                              4,070
repolist: 4,070
[root@localhost yum.repos.d]# yum install vim -y
已加载插件：fastestmirror
Loading mirror speeds from cached hostfile
正在解决依赖关系
--> 正在检查事务
---> 软件包 vim-enhanced.x86_64.2.7.4.629-7.el7 将被 安装
--> 正在处理依赖关系 vim-common = 2:7.4.629-7.el7，它被软件包 2:vim-enhanced-7.4.629-7.el7.x86_64 需要
--> 正在处理依赖关系 libgpm.so.2()(64bit)，它被软件包 2:vim-enhanced-7.4.629-7.el7.x86_64 需要
--> 正在检查事务
---> 软件包 gpm-libs.x86_64.0.1.20.7-6.el7 将被 安装
---> 软件包 vim-common.x86_64.2.7.4.629-7.el7 将被 安装
--> 正在处理依赖关系 vim-filesystem，它被软件包 2:vim-common-7.4.629-7.el7.x86_64 需要
--> 正在检查事务
---> 软件包 vim-filesystem.x86_64.2.7.4.629-7.el7 将被 安装
--> 解决依赖关系完成

依赖关系解决

================================================================================
 Package               架构          版本                    源            大小
================================================================================
正在安装:
 vim-enhanced          x86_64        2:7.4.629-7.el7         local        1.1 M
为依赖而安装:
 gpm-libs              x86_64        1.20.7-6.el7            local         32 k
 vim-common            x86_64        2:7.4.629-7.el7         local        5.9 M
 vim-filesystem        x86_64        2:7.4.629-7.el7         local         11 k

事务概要
================================================================================
安装  1 软件包 (+3 依赖软件包)

总下载量：7.0 M
安装大小：23 M
Downloading packages:
--------------------------------------------------------------------------------
总计                                                44 MB/s | 7.0 MB  00:00
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  正在安装    : 2:vim-filesystem-7.4.629-7.el7.x86_64                       1/4
  正在安装    : 2:vim-common-7.4.629-7.el7.x86_64                           2/4
  正在安装    : gpm-libs-1.20.7-6.el7.x86_64                                3/4
  正在安装    : 2:vim-enhanced-7.4.629-7.el7.x86_64                         4/4
  验证中      : 2:vim-common-7.4.629-7.el7.x86_64                           1/4
  验证中      : gpm-libs-1.20.7-6.el7.x86_64                                2/4
  验证中      : 2:vim-filesystem-7.4.629-7.el7.x86_64                       3/4
  验证中      : 2:vim-enhanced-7.4.629-7.el7.x86_64                         4/4

已安装:
  vim-enhanced.x86_64 2:7.4.629-7.el7

作为依赖被安装:
  gpm-libs.x86_64 0:1.20.7-6.el7           vim-common.x86_64 2:7.4.629-7.el7
  vim-filesystem.x86_64 2:7.4.629-7.el7

完毕！
[root@localhost yum.repos.d]# rpm -qlvsftpd
rpm: -qlvsftpd: 未知的选项
[root@localhost yum.repos.d]# rpm -ql vsftpd
未安装软件包 vsftpd
[root@localhost yum.repos.d]# ss -naltp |grep vsftpd
[root@localhost yum.repos.d]# yum install vsftpd -y
已加载插件：fastestmirror
Loading mirror speeds from cached hostfile
正在解决依赖关系
--> 正在检查事务
---> 软件包 vsftpd.x86_64.0.3.0.2-28.el7 将被 安装
--> 解决依赖关系完成

依赖关系解决

================================================================================
 Package          架构             版本                   源               大小
================================================================================
正在安装:
 vsftpd           x86_64           3.0.2-28.el7           local           172 k

事务概要
================================================================================
安装  1 软件包

总下载量：172 k
安装大小：353 k
Downloading packages:
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  正在安装    : vsftpd-3.0.2-28.el7.x86_64                                  1/1
  验证中      : vsftpd-3.0.2-28.el7.x86_64                                  1/1

已安装:
  vsftpd.x86_64 0:3.0.2-28.el7

完毕！
[root@localhost yum.repos.d]# ss -naltp |grep vsftpd
[root@localhost yum.repos.d]# rpm -ql vsftpd
/etc/logrotate.d/vsftpd
/etc/pam.d/vsftpd
/etc/vsftpd
/etc/vsftpd/ftpusers
/etc/vsftpd/user_list
/etc/vsftpd/vsftpd.conf
/etc/vsftpd/vsftpd_conf_migrate.sh
/usr/lib/systemd/system-generators/vsftpd-generator
/usr/lib/systemd/system/vsftpd.service
/usr/lib/systemd/system/vsftpd.target
/usr/lib/systemd/system/vsftpd@.service
/usr/sbin/vsftpd
/usr/share/doc/vsftpd-3.0.2
/usr/share/doc/vsftpd-3.0.2/AUDIT
/usr/share/doc/vsftpd-3.0.2/BENCHMARKS
/usr/share/doc/vsftpd-3.0.2/BUGS
/usr/share/doc/vsftpd-3.0.2/COPYING
/usr/share/doc/vsftpd-3.0.2/Changelog
/usr/share/doc/vsftpd-3.0.2/EXAMPLE
/usr/share/doc/vsftpd-3.0.2/EXAMPLE/INTERNET_SITE
/usr/share/doc/vsftpd-3.0.2/EXAMPLE/INTERNET_SITE/README
/usr/share/doc/vsftpd-3.0.2/EXAMPLE/INTERNET_SITE/README.configuration
/usr/share/doc/vsftpd-3.0.2/EXAMPLE/INTERNET_SITE/vsftpd.conf
/usr/share/doc/vsftpd-3.0.2/EXAMPLE/INTERNET_SITE/vsftpd.xinetd
/usr/share/doc/vsftpd-3.0.2/EXAMPLE/INTERNET_SITE_NOINETD
/usr/share/doc/vsftpd-3.0.2/EXAMPLE/INTERNET_SITE_NOINETD/README
/usr/share/doc/vsftpd-3.0.2/EXAMPLE/INTERNET_SITE_NOINETD/README.configuration
/usr/share/doc/vsftpd-3.0.2/EXAMPLE/INTERNET_SITE_NOINETD/vsftpd.conf
/usr/share/doc/vsftpd-3.0.2/EXAMPLE/PER_IP_CONFIG
/usr/share/doc/vsftpd-3.0.2/EXAMPLE/PER_IP_CONFIG/README
/usr/share/doc/vsftpd-3.0.2/EXAMPLE/PER_IP_CONFIG/README.configuration
/usr/share/doc/vsftpd-3.0.2/EXAMPLE/PER_IP_CONFIG/hosts.allow
/usr/share/doc/vsftpd-3.0.2/EXAMPLE/README
/usr/share/doc/vsftpd-3.0.2/EXAMPLE/VIRTUAL_HOSTS
/usr/share/doc/vsftpd-3.0.2/EXAMPLE/VIRTUAL_HOSTS/README
/usr/share/doc/vsftpd-3.0.2/EXAMPLE/VIRTUAL_USERS
/usr/share/doc/vsftpd-3.0.2/EXAMPLE/VIRTUAL_USERS/README
/usr/share/doc/vsftpd-3.0.2/EXAMPLE/VIRTUAL_USERS/README.configuration
/usr/share/doc/vsftpd-3.0.2/EXAMPLE/VIRTUAL_USERS/logins.txt
/usr/share/doc/vsftpd-3.0.2/EXAMPLE/VIRTUAL_USERS/vsftpd.conf
/usr/share/doc/vsftpd-3.0.2/EXAMPLE/VIRTUAL_USERS/vsftpd.pam
/usr/share/doc/vsftpd-3.0.2/EXAMPLE/VIRTUAL_USERS_2
/usr/share/doc/vsftpd-3.0.2/EXAMPLE/VIRTUAL_USERS_2/README
/usr/share/doc/vsftpd-3.0.2/FAQ
/usr/share/doc/vsftpd-3.0.2/INSTALL
/usr/share/doc/vsftpd-3.0.2/LICENSE
/usr/share/doc/vsftpd-3.0.2/README
/usr/share/doc/vsftpd-3.0.2/README.security
/usr/share/doc/vsftpd-3.0.2/REWARD
/usr/share/doc/vsftpd-3.0.2/SECURITY
/usr/share/doc/vsftpd-3.0.2/SECURITY/DESIGN
/usr/share/doc/vsftpd-3.0.2/SECURITY/IMPLEMENTATION
/usr/share/doc/vsftpd-3.0.2/SECURITY/OVERVIEW
/usr/share/doc/vsftpd-3.0.2/SECURITY/TRUST
/usr/share/doc/vsftpd-3.0.2/SIZE
/usr/share/doc/vsftpd-3.0.2/SPEED
/usr/share/doc/vsftpd-3.0.2/TODO
/usr/share/doc/vsftpd-3.0.2/TUNING
/usr/share/doc/vsftpd-3.0.2/vsftpd.xinetd
/usr/share/man/man5/vsftpd.conf.5.gz
/usr/share/man/man8/vsftpd.8.gz
/var/ftp
/var/ftp/pub
[root@localhost yum.repos.d]# systemctl restart vsftpd
[root@localhost yum.repos.d]# ss -naltp |grep vsftpd
LISTEN     0      32        [::]:21                    [::]:*                   users:(("vsftpd",pid=23514,fd=4))
[root@localhost yum.repos.d]# a=(`ss -naltp|grep vsftpd`)
[root@localhost yum.repos.d]# echo $a
LISTEN
[root@localhost yum.repos.d]# echo ${a[@]}
LISTEN 0 32 [::]:21 [::]:* users:(("vsftpd",pid=23514,fd=4))
[root@localhost yum.repos.d]# b=(`echo ${a[@]}|cut -d ":" -f4`)
[root@localhost yum.repos.d]# echo $b
21
[root@localhost yum.repos.d]# c=("echo $[a[@]|cut -d ":" -f8")
> ^C
[root@localhost yum.repos.d]# c=("echo ${a[@]}|cut -d ":" -f8")
[root@localhost yum.repos.d]# echo $c
echo LISTEN
[root@localhost yum.repos.d]# echo {c[@]}
{c[@]}
[root@localhost yum.repos.d]# echo ${c[@]}
echo LISTEN 0 32 [::]:21 [::]:* users:(("vsftpd",pid=23514,fd=4))|cut -d : -f8
[root@localhost yum.repos.d]# pid1=(`echo ${a[@]}|cut -d ":" -f8`)
[root@localhost yum.repos.d]# echo $pid1
(("vsftpd",pid=23514,fd=4))
[root@localhost yum.repos.d]# d=("echo ${a[@]}|cut -d ":" -f8")
[root@localhost yum.repos.d]# echo $d
echo LISTEN
[root@localhost yum.repos.d]# echo ${d[@]}
echo LISTEN 0 32 [::]:21 [::]:* users:(("vsftpd",pid=23514,fd=4))|cut -d : -f8
[root@localhost yum.repos.d]# d=("echo ${a[@]}|cut -d ":" -f6")
[root@localhost yum.repos.d]# echo $d
echo LISTEN
[root@localhost yum.repos.d]# echo ${d[@]}
echo LISTEN 0 32 [::]:21 [::]:* users:(("vsftpd",pid=23514,fd=4))|cut -d : -f6
[root@localhost yum.repos.d]#
bash 复制代码 
root@192.168.235.20's password:
     ┌────────────────────────────────────────────────────────────────────┐
     │                        • MobaXterm 20.0 •                          │
     │            (SSH client, X-server and networking tools)             │
     │                                                                    │
     │ ➤ SSH session to root@192.168.235.20                               │
     │   • SSH compression : ✘                                            │
     │   • SSH-browser     : ✔                                            │
     │   • X11-forwarding  : ✔  (remote display is forwarded through SSH) │
     │   • DISPLAY         : ✔  (automatically set on remote server)      │
     │                                                                    │
     │ ➤ For more info, ctrl+click on help or visit our website           │
     └────────────────────────────────────────────────────────────────────┘

Last login: Sun Aug 10 20:54:48 2025 from 192.168.235.1
[root@web ~]# ls
1828.txt  anaconda-ks.cfg         axel-2.4.tar.gz  for5.sh                    null               process1.sh   testfor2.sh  user.sh
1837.txt  app                     bb.conf          httpd-2.4.37               ok                 process.sh    testfor3.sh  vsftpd1.sh
1.txt     apr-1.5.2               cc.conf          httpd-2.4.37.tar.bz2       okl                readme7       testfor4.sh  vsftpd2.sh
2-1.java  apr-1.5.2.tar.bz2       code             initial-setup-ks.cfg       php-7.2.17         readme.txt    testfor.sh   vsftpd.sh
2.java    apr-util-1.5.4          dir1             inotify-tools-3.13.tar.gz  php-7.2.17.tar.xz  serverOk.sh   uname2.sh    vstest.sh
=6        apr-util-1.5.4.tar.bz2  file20.java      mysql-5.6.31               ping2.sh           service-s.sh  uname.sh     wordpress
alll1     axel-2.4                file23.java      mysql-5.6.31.tar.gz        ping.sh            Steam.dll     url.sh       wordpress-4.7.3-zh_CN.tar.gz
[root@web ~]# vim vsftpdok.sh
您在 /var/spool/mail/root 中有新邮件
[root@web ~]# cat vsftpdok.sh
rpm -ql vsftpd >/dev/null 2>&1
if [ $? -eq 0 ];then
echo "OK"
else
yum install vsftpd -y
if [ $? -eq 0 ];then
echo "install ok"
else
echo "not install"
fi
fi
[root@web ~]# chmod +x vsftpdok.sh
您在 /var/spool/mail/root 中有邮件
[root@web ~]# ./vsftpdok.sh
OK
[root@web ~]# uname -rr
3.10.0-1160.el7.x86_64
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[root@web ~]# a=("uname -r")
[root@web ~]# echo $a
uname -r
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[root@web ~]# a=(`uname -r`)
[root@web ~]# echo $a
3.10.0-1160.el7.x86_64
[root@web ~]# echo "$(hostname)"
web.cn
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[root@web ~]# echo $hostname

[root@web ~]# echo $(hostname)
web.cn
[root@web ~]# echo $`hostname`
$web.cn
您在 /var/spool/mail/root 中有邮件
[root@web ~]# echo $(uname -r)
3.10.0-1160.el7.x86_64
[root@web ~]# a=$(uname -r)
您在 /var/spool/mail/root 中有邮件
[root@web ~]# echo $a
3.10.0-1160.el7.x86_64
[root@web ~]# main={$(echo $a|cut -d "." -f1)}
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[root@web ~]# echo $main
{3}
[root@web ~]# e={1,2,3}
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[root@web ~]# echo $e
{1,2,3}
[root@web ~]# main1=$(echo $a|cut -d "." -f1)
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[root@web ~]# echo $main1
3
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[root@web ~]# extra=`echo $a|cut -d "." -f2`
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[root@web ~]# echo $extra
10
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[root@web ~]# vim unameok.sh
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[root@web ~]# cat unameok.sh
a=$(uname -r)
echo $a
if [ $? -eq 0 ];then
main=`echo $a|cut -d "." -f1`
extra=`echo $b|cut -d "." -f2`
echo $main
echo $extra
if [ $main eq 2 ]&&[ $extra >= 6];then
echo $a
else echo "wrong"
fi
fi
[root@web ~]# chmod +x unameok.sh
您在 /var/spool/mail/root 中有邮件
[root@web ~]# ./unameok.sh
3.10.0-1160.el7.x86_64
3

./unameok.sh: 第 8 行:[: eq: 期待二元表达式
wrong
[root@web ~]# vim unameok.sh
您在 /var/spool/mail/root 中有邮件
[root@web ~]# cat unameok.sh
a=$(uname -r)
echo $a
if [ $? -eq 0 ];then
main=`echo $a|cut -d "." -f1`
extra=`echo $a|cut -d "." -f2`
echo $main
echo $extra
if [ $main eq 2 ]&&[ $extra >= 6 ];then
echo $a
else echo "wrong"
fi
fi
[root@web ~]# ./unameok.sh
3.10.0-1160.el7.x86_64
3
10
./unameok.sh: 第 8 行:[: eq: 期待二元表达式
wrong
[root@web ~]# vim unameok.sh
您在 /var/spool/mail/root 中有邮件
[root@web ~]# cat unameok.sh
a=$(uname -r)
echo $a
if [ $? -eq 0 ];then
main=`echo $a|cut -d "." -f1`
extra=`echo $a|cut -d "." -f2`
echo $main
echo $extra
if [ $main == 2 ]&&[ $extra >= 6 ];then
echo $a
else echo "wrong"
fi
fi
[root@web ~]# ./unameok.sh
3.10.0-1160.el7.x86_64
3
10
wrong
[root@web ~]# ss -naltp |grep vsftpd
LISTEN     0      32        [::]:21                    [::]:*                   users:(("vsftpd",pid=1735,fd=4))
[root@web ~]# all=$(ss -naltp|grep vsftpd)
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[root@web ~]# echo $all
LISTEN 0 32 [::]:21 [::]:* users:(("vsftpd",pid=1735,fd=4))
[root@web ~]# port=`echo $all|cut -d ":" -f4`
[root@web ~]# echo $port
21 [
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[root@web ~]# realport=`echo $port|cut -c1-2`
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[root@web ~]# echo $realport
21
[root@web ~]# pid=`echo $all|cut -d ":" -f8`
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[root@web ~]# echo $pid
(("vsftpd",pid=1735,fd=4))
[root@web ~]# readpid=`echo $pid|cut -d "," -f2`
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[root@web ~]# echo $readpid
pid=1735
[root@web ~]# vim ftpok.sh
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[root@web ~]# cat ftpok.sh
a=$(ss -naltp|grep vsftpd)
if [ $? == 0 ];then
port=`echo $a|cut -d ":" -f4`
realport=`echo $port|cut -c1-2`
pid=`echo $a|cut -d ":" -f8`
realpid=`echo $pid|cut -d "," -f2`


[root@web ~]# vim ftpok.sh
您在 /var/spool/mail/root 中有邮件
[root@web ~]# cat ftpok.sh
a=$(ss -naltp|grep vsftpd)
if [ $? == 0 ];then
port=`echo $a|cut -d ":" -f4`
realport=`echo $port|cut -c1-2`
pid=`echo $a|cut -d ":" -f8`
realpid=`echo $pid|cut -d "," -f2`
echo "vsftpd.server has been started"
echo "vsftpd listen on:"$realport
echo "vsftpd's process pid is:"$realpid
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[root@web ~]# chmod +x ftpok.sh
[root@web ~]# ./ftpok.sh
./ftpok.sh:行10: 语法错误: 未预期的文件结尾
[root@web ~]# vim ftpok.sh
您在 /var/spool/mail/root 中有邮件
[root@web ~]# cat ftpok.sh
a=$(ss -naltp|grep vsftpd)
if [ $? == 0 ];then
port=`echo $a|cut -d ":" -f4`
realport=`echo $port|cut -c1-2`
pid=`echo $a|cut -d ":" -f8`
realpid=`echo $pid|cut -d "," -f2`
echo "vsftpd.server has been started"
echo "vsftpd listen on:"$realport
echo "vsftpd's process pid is:"$realpid
else
echo "vsftpd not start"
fi
[root@web ~]# ./ftpok.sh
vsftpd.server has been started
vsftpd listen on:21
vsftpd's process pid is:pid=1735
[root@web ~]# ss -naltp |grep vsftpd
LISTEN     0      32        [::]:21                    [::]:*                   users:(("vsftpd",pid=1735,fd=4))
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[root@web ~]# vim testfor.sh
您在 /var/spool/mail/root 中有邮件
[root@web ~]# vim testcfor.sh
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[root@web ~]# cat testcfor.sh
for (( i=1;i<=5;i++))
       do
            echo $i
       done

[root@web ~]# chmod +x testcfor.sh
[root@web ~]# ./testcfor.sh
1
2
3
4
5
[root@web ~]# vim testcfor.sh
您在 /var/spool/mail/root 中有邮件
[root@web ~]# cat testcfor.sh
for (( i=1;i<=5;i++))
       do
            echo $i
       done
for (( i=1;i<=5;i++))
do
echo $i
done
for ((i=1;i<=10;i+=2))
do
echo $i
done
for ((i=2;i<=10;i+=2))
do
echo $i
done
[root@web ~]# ./testcfor.sh
1
2
3
4
5
1
2
3
4
5
1
3
5
7
9
2
4
6
8
10
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[root@web ~]# for (i=1;i<=100;i+=2)
-bash: 未预期的符号 `(' 附近有语法错误
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[root@web ~]# for (( i=1;i<=100;i+=2 ))
> do
> ^C
[root@web ~]# sum=0
[root@web ~]# for (( i=1;i<=100;i+=2 ))
> do
> sum+=i
> done
您在 /var/spool/mail/root 中有邮件
[root@web ~]# echo $sum
0iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii
[root@web ~]# declare -i sum=0
[root@web ~]# for (( i=1;i<=100;i+=2 ))
> do
> sum+=i
> done
[root@web ~]# echo $sum
2500
[root@web ~]# vim sum.sh
您在 /var/spool/mail/root 中有邮件
[root@web ~]# cat sum.sh
declare -i sum=0
for (( i=1;i<=100:i+=2))
do
sum+=i
done
echo "sum is:"$sum
[root@web ~]# chmod +x sum.sh
[root@web ~]# ./sum.sh
./sum.sh:行2: 语法错误: 需要算数表达式
./sum.sh:行2: 语法错误: `(( i=1;i<=100:i+=2))'
sum is:0
[root@web ~]# vim sum.sh
您在 /var/spool/mail/root 中有邮件
[root@web ~]# cat sum.sh
declare -i sum=0
for (( i=1;i<=100;i+=2 ))
do
sum+=i
done
echo "sum is:"$sum
[root@web ~]# ./sum.sh
sum is:2500
[root@web ~]# vim for5.sh
您在 /var/spool/mail/root 中有邮件
[root@web ~]# vim for51.sh
您在 /var/spool/mail/root 中有邮件
[root@web ~]# cat for51.sh
for i in {1..5}
do
test $i -eq 2 && break || touch /tmp/ffile$i
done
echo lllllll
您在 /var/spool/mail/root 中有邮件
[root@web ~]# ls /tmp
1.txt                sys-20250804.tar.gz
2.txt                sys-20250805.tar.gz
3.txt                sys-20250806.tar.gz
5.txt                sys-20250807.tar.gz
6.txt                sys-20250810.tar.gz
abc.txt              sys-20250811.tar.gz
dir1                 systemd-private-6f37c267bc534142983b62ad1ab0be9a-bolt.service-LMvltW
dir2                 systemd-private-6f37c267bc534142983b62ad1ab0be9a-chronyd.service-UWJorp
file1                systemd-private-6f37c267bc534142983b62ad1ab0be9a-colord.service-tLvcX3
file2                systemd-private-6f37c267bc534142983b62ad1ab0be9a-cups.service-LjtpWQ
file3.patch          systemd-private-6f37c267bc534142983b62ad1ab0be9a-rtkit-daemon.service-gttbXa
file5                systemd-private-e06954d935da43dd9840443262c2b912-bolt.service-Shxrsd
file6.patch          systemd-private-e06954d935da43dd9840443262c2b912-chronyd.service-NvD4bP
file.patch           systemd-private-e06954d935da43dd9840443262c2b912-colord.service-N0eYTb
passwd               systemd-private-e06954d935da43dd9840443262c2b912-cups.service-xuO8Nz
swapfile             systemd-private-e06954d935da43dd9840443262c2b912-rtkit-daemon.service-BM4Ksb
sys-20250728.tar.gz  vmware-root_1022-2999133054
sys-20250729.tar.gz  vmware-root_1207-3979642956
sys-20250730.tar.gz  vmware-root_1329-4256610699
sys-20250731.tar.gz  vmware-root_845-4021653450
sys-20250801.tar.gz  vmware-root_971-4290232077
sys-20250803.tar.gz
[root@web ~]# ./for51.sh
-bash: ./for51.sh: 权限不够
[root@web ~]# chomod +x for51.sh
bash: chomod: 未找到命令...
您在 /var/spool/mail/root 中有邮件
[root@web ~]# chmod +x for51.sh
[root@web ~]# ./for51.sh
lllllll
[root@web ~]# ls /tmp
1.txt                sys-20250803.tar.gz
2.txt                sys-20250804.tar.gz
3.txt                sys-20250805.tar.gz
5.txt                sys-20250806.tar.gz
6.txt                sys-20250807.tar.gz
abc.txt              sys-20250810.tar.gz
dir1                 sys-20250811.tar.gz
dir2                 systemd-private-6f37c267bc534142983b62ad1ab0be9a-bolt.service-LMvltW
ffile1               systemd-private-6f37c267bc534142983b62ad1ab0be9a-chronyd.service-UWJorp
file1                systemd-private-6f37c267bc534142983b62ad1ab0be9a-colord.service-tLvcX3
file2                systemd-private-6f37c267bc534142983b62ad1ab0be9a-cups.service-LjtpWQ
file3.patch          systemd-private-6f37c267bc534142983b62ad1ab0be9a-rtkit-daemon.service-gttbXa
file5                systemd-private-e06954d935da43dd9840443262c2b912-bolt.service-Shxrsd
file6.patch          systemd-private-e06954d935da43dd9840443262c2b912-chronyd.service-NvD4bP
file.patch           systemd-private-e06954d935da43dd9840443262c2b912-colord.service-N0eYTb
passwd               systemd-private-e06954d935da43dd9840443262c2b912-cups.service-xuO8Nz
swapfile             systemd-private-e06954d935da43dd9840443262c2b912-rtkit-daemon.service-BM4Ksb
sys-20250728.tar.gz  vmware-root_1022-2999133054
sys-20250729.tar.gz  vmware-root_1207-3979642956
sys-20250730.tar.gz  vmware-root_1329-4256610699
sys-20250731.tar.gz  vmware-root_845-4021653450
sys-20250801.tar.gz  vmware-root_971-4290232077
[root@web ~]# declare -i n
您在 /var/spool/mail/root 中有邮件
[root@web ~]# for (( i=1;i<=n;i++ ))
> do
> if [ n%i==0 ];then
> if [ i==1 || i==n ];then
> ^C
您在 /var/spool/mail/root 中有邮件
[root@web ~]# for (( i==1;i<=n;i++ ))
> do if [ i !=1 ] && [ i!=n ] && [ n%i == 0 ];then
> echo "i is not sushu "
> else echo "i is sushu"
> fi
> done
您在 /var/spool/mail/root 中有邮件
[root@web ~]# vim judgeprime.sh
您在 /var/spool/mail/root 中有邮件
[root@web ~]# cat judgeprime.sh
declare -i n
read -p "please input a number:" $n
for i in {1..n}
do
if [ i != 1 ] && [ i != $n ] && [ $n%i == 0 ];then
echo $n" is a prime number " && break
else
fi
done
echo $n"is a prime number"

[root@web ~]# chmod +x judgeprime.sh
[root@web ~]# ./judgeprime.sh
please input a number:2
./judgeprime.sh:行8: 未预期的符号 `fi' 附近有语法错误
./judgeprime.sh:行8: `fi'
[root@web ~]# vim judgeprime.sh
您在 /var/spool/mail/root 中有邮件
[root@web ~]# cat judgeprime.sh
declare -i n
read -p "please input a number:" n
for (( i=1;i<=n;i++ ))
do
if [ i != 1 ] && [ i != $n ] && [ $(($n%i == 0)) ];then
echo $n" is not prime number " && break
else
fi
done
echo $n"is a prime number"

[root@web ~]# ./judgeprime.sh
please input a number:3
./judgeprime.sh:行8: 未预期的符号 `fi' 附近有语法错误
./judgeprime.sh:行8: `fi '
您在 /var/spool/mail/root 中有邮件
[root@web ~]#
Network error: Software caused connection abort

─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────

Session stopped
    - Press <return> to exit tab
    - Press R to restart session
    - Press S to save terminal output to file
root@192.168.235.20's password:
     ┌────────────────────────────────────────────────────────────────────┐
     │                        • MobaXterm 20.0 •                          │
     │            (SSH client, X-server and networking tools)             │
     │                                                                    │
     │ ➤ SSH session to root@192.168.235.20                               │
     │   • SSH compression : ✘                                            │
     │   • SSH-browser     : ✔                                            │
     │   • X11-forwarding  : ✔  (remote display is forwarded through SSH) │
     │   • DISPLAY         : ✔  (automatically set on remote server)      │
     │                                                                    │
     │ ➤ For more info, ctrl+click on help or visit our website           │
     └────────────────────────────────────────────────────────────────────┘

Last login: Mon Aug 11 19:07:38 2025 from 192.168.235.1
[root@web ~]# cat judgeprime.sh
declare -i n
read -p "please input a number:" n
for (( i=1;i<=n;i++ ))
do
if [ i != 1 ] && [ i != $n ] && [ $(($n%i == 0)) ];then
echo $n" is not prime number " && break
else
fi
done
echo $n"is a prime number"

[root@web ~]# vim judgeprime.sh
您在 /var/spool/mail/root 中有新邮件
[root@web ~]# cat judgeprime.sh
declare -i n
read -p "please input a number:" n
if (( n <= 1));
echo "n is not a prime number"
exit 0
fi
for (( i=1;i<=n;i++ ))
do
if [ i != 1 ] && [ i != $n ] && [ $(($n%i == 0)) ];then
echo $n" is not prime number " && break
fi
done
echo $n"is a prime number"

[root@web ~]# ./judgeprime.sh
please input a number:2
./judgeprime.sh:行6: 未预期的符号 `fi' 附近有语法错误
./judgeprime.sh:行6: `fi'
您在 /var/spool/mail/root 中有邮件
[root@web ~]# vim judgeprime.sh
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[root@web ~]# cat judgeprime.sh
declare -i n
read -p "please input a number:" n
if [ n <= 1 ];then
echo "n is not a prime number"
exit 0
fi
for (( i=1;i<=n;i++ ))
do
if [ i != 1 ] && [ i != $n ] && [ $(($n%i == 0)) ];then
echo $n" is not prime number " && break
fi
done
echo $n"is a prime number"

[root@web ~]# ./judgeprime.sh
please input a number:4
./judgeprime.sh:行3: =: 没有那个文件或目录
4 is not prime number
4is a prime number
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[root@web ~]# ./judgeprime.sh
please input a number:1
./judgeprime.sh:行3: =: 没有那个文件或目录
1 is not prime number
1is a prime number
[root@web ~]# vim judgeprime.sh
您在 /var/spool/mail/root 中有邮件
[root@web ~]# cat judgeprime.sh
declare -i n
read -p "please input a number:" n
if [ $n <= 1 ];then
echo "n is not a prime number"
exit 0
fi
is_prime=0
for (( i=1;i<=n;i++ ))
do
if [ i != 1 ] && [ i != $n ] && [ $(($n%i == 0)) ];then
is_prime=1
break
fi
done
if [ is_prime == 0 ];then
echo $n " is a prime number "
else
echo $n " is not prime number"


[root@web ~]# ./judgeprime.sh
please input a number:2
./judgeprime.sh:行3: =: 没有那个文件或目录
./judgeprime.sh:行21: 语法错误: 未预期的文件结尾
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[root@web ~]# vim judgeprime.sh
[root@web ~]# cat judgeprime.sh
declare -i n
read -p "please input a number:" n
if [ $n <= 1 ];then
echo "n is not a prime number"
exit 0
fi
is_prime=0
for (( i=1;i<=n;i++ ))
do
if [ i != 1 ] && [ i != $n ] && [ $(($n%i == 0)) ];then
is_prime=1
break
fi
done
if [ is_prime == 0 ];then
echo $n " is a prime number "
else
echo $n " is not prime number"
fi

您在 /var/spool/mail/root 中有邮件
[root@web ~]# ./judgeprime.sh
please input a number:2
./judgeprime.sh:行3: =: 没有那个文件或目录
2  is not prime number
[root@web ~]# vim judgeprime.sh
您在 /var/spool/mail/root 中有邮件
[root@web ~]# ./judgeprime.sh
please input a number:1
./judgeprime.sh:行3: =: 没有那个文件或目录
1  is not prime number
[root@web ~]# vim judgeprime.sh
您在 /var/spool/mail/root 中有邮件
[root@web ~]# cat judgeprime.sh
declare -i n
read -p "please input a number:" n
if [ $n -le 1 ];then
echo "n is not a prime number"
exit 0
fi
is_prime=0
for (( i=1;i<=n;i++ ))
do
if [ i != 1 ] && [ i != $n ] && [ $(($n%i == 0)) ];then
is_prime=1
break
fi
done
if [ is_prime == 0 ];then
echo $n " is a prime number "
else
echo $n " is not prime number"
fi

[root@web ~]# ./judgeprime.sh
please input a number:1
n is not a prime number
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[root@web ~]# ./judgeprime.sh
please input a number:5
5  is not prime number
[root@web ~]#
bash 复制代码 
[root@web ~]# ./judgeprime.sh
please input a number:1
n is not a prime number
您在 /var/spool/mail/root 中有邮件
[root@web ~]# ./judgeprime.sh
please input a number:5
5  is not prime number
[root@web ~]# vim judgeprime,sh
您在 /var/spool/mail/root 中有邮件
[root@web ~]# vim judgeprime.sj
[root@web ~]# vim judgeprime.sh
您在 /var/spool/mail/root 中有邮件
[root@web ~]# cat judgeprime.sh
declare -i n
read -p "please input a number:" n
if [ $n -le 1 ];then
echo "n is not a prime number"
exit 0
fi
is_prime=0
for (( i=1;i<=n;i++ ))
do
if [ i != 1 ] && [ i != $n ] && [ $(($n%i)) == 0 ];then
is_prime=1
break
fi
done
if [ is_prime == 0 ];then
echo $n " is a prime number "
else
echo $n " is not prime number"
fi

[root@web ~]# ./judgeprime.sh
please input a number:5
5  is not prime number
[root@web ~]#
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