The definition and use of shell script function

use of function functions

Defining functions

1)

Function name () {

...

...

}

2)

Function name {

...

...

}

Calling functions

Function name

You can also pass parameters to a function by positional variables

Example:

Scripting, Implementing directory management functions, requiring the use of functions

#!/bin/bash

#

Createdir () {

Read-p "Enter directory:" dir

If [-D $dir]; Then

echo "Directory $dir exists"

Else

Mkdir-p $dir

echo "Directory $dir creation Complete"

Fi

}

RemoveDir () {

Read-p "Enter directory:" dir

If [-D $dir]; Then

RM-RF $dir

echo "Directory $dir Delete Complete"

Else

echo "Directory $dir does not exist"

Fi

}

Cat << EOF

===================

Directory Management

1. Create a Directory

2. Delete Directory

3. Exit script

==================

Eof

Echo

While true; Do

Read-p "Please enter your choice:" Choice

Case $choice in

1)

Createdir

;;

2)

RemoveDir

;;

3)

Exit 0

;;

*)

ECHO-E "\033[31m input Error! \033[0m "

;;

Esac

Done

Write scripts to implement user management functions

#!/bin/bash

#

CreateUser () {

Read-p "Enter User:" Name

if! ID $name &>/dev/null; Then

Useradd $name

Read-p "Enter Password:" Password

echo "$password" | passwd--stdin $name &>/dev/null

echo "User $name creation Complete"

Else

echo "User $name not present."

Fi

}

Removeuser () {

If ID $ &>/dev/null; Then

Userdel-r $

echo "User Delete complete"

Else

echo "User $ not present"

Fi

}

ModifyUser () {

Read-p "Enter User:" Name

If ID $name &>/dev/null; Then

sh_name=$ (grep "^ $name:"/etc/passwd | Awk-f: ' {print $7} ')

echo "User $name current shell: $sh _name"

Echo

echo "System Current Shell:"

Cat-n/etc/shells

Echo

Read-p "Please enter the shell to be modified:" New_sh_name

Usermod-s $new _sh_name $name

echo "User $name shell has been modified to $new_sh_name"

Else

echo "User $name not Present"

Fi

}

Cat << EOF

===============

User Management

1. Create user

2. Delete users

3. Modify the user shell

4. Exit script

===============

Eof

Echo

While true; Do

Read-p "Please enter your choice:" Choice

Case $choice in

1)

CreateUser

;;

2)

Read-p "Enter User:" Name

Removeuser $name

;;

3)

ModifyUser

;;

4)

Exit 0

;;

*)

echo "Input Error! "

;;

Esac

Done

Nginx Service Control Script:

Installing Nginx

[email protected] ~]# Yum install-y gcc pcre-devel zlib-devel openssl-devel

[Email protected] ~]# Tar XF nginx-1.11.4.tar.gz

[Email protected] ~]# CD nginx-1.11.4/

[Email protected] nginx-1.11.4]#/configure--prefix=/usr/local/nginx

[[email protected] nginx-1.11.4]# make && make install

The script is as follows:

#!/bin/bash

#

Nginx_cmd=/usr/local/nginx/sbin/nginx

Nginx_conf=/usr/local/nginx/conf/nginx.conf

Nginx_pid_file=/usr/local/nginx/logs/nginx.pid

Start () {

$nginx _cmd

If [$?-eq 0]; Then

echo "Service Nginx start ... [OK] "

Fi

}

Stop () {

$nginx _cmd-s Stop

}

Reload () {

If $nginx _cmd-t &>/dev/null; Then

$nginx _cmd-s Reload

Else

$nginx _cmd-t

Fi

}

Status () {

If [-e $nginx _pid_file]; Then

echo "Service Nginx (PID ' cat $nginx _pid_file ') is running ..."

Else

echo "Service Nginx is stopped ..."

Fi

}

If [-z]; Then

echo "using: $ {start|stop|restart|reload|status}"

Exit 9

Fi

Case $ in

Start

Start

;;

Stop

Stop

;;

Restart

Stop

Sleep 2

Start

;;

Reload

Reload

;;

Status

Status

;;

*)

echo "using: $ {start|stop|restart|reload|status}"

Exit 8

Esac

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The definition and use of shell script function