14.4.2.7 Lab – Write Basic Scripts in Windows and Linux
Instructor Note: Red font color or gray highlights indicate text that appears in the Instructor copy only.
Objectives
In this lab, you will write basic scripts in different scripting languages to help understand how each language handles automating tasks.
Background / Scenario
Writing scripts to automate common administration functions saves time and gives the administrator flexibility to perform other tasks. In the lab, you will write three types of scripts that will perform similar tasks. Compare the different languages as you automate some simple task.
Required Resources
- Windows PC
- VM running a Linux distribution
Instructions
Step 1: Create a Windows batch script.
a. In a text editor, such as Notepad, save a text file named info.bat in your home directory (C:\Users\yourusername) with the following text:
@echo off echo Computer Name is: %computername% echo Windows version is: ver echo CPU is: %PROCESSOR_IDENTIFIER% echo Total memory is: rem Windows Management Instrumentation Command (WMIC) is a command line utility that can retrieve information about local or remote computers. For more inline information, enter help wmic or wmic /? at the command prompt. wmic ComputerSystem get TotalPhysicalMemory echo The disks that are installed and their freespace: wmic logicaldisk get size,freespace,caption echo All the %computername% IP addresses rem netsh is a command line scripting utility that allows the users to view or modify the network configurations of a running computer. For more inline information, enter nesh /? at the command prompt. rem findstr is used for searching for a text string in files. For more inline information, enter findstr /? at the command prompt. netsh interface ip show address | findstr "IP Address"
b. Open a command prompt and navigate to your home directory.
c. List the content of your home directory and verify that the file info.bat is saved with the correct file. If not, rename the file, for example, rename info.bat.txt info.bat.
d. At the prompt, enter info.bat to run the script.
Questions:
What was the output?
Answers will vary
Computer Name is: KDV-PC
Windows version is:
Microsoft Windows [Version 10.0.17763.437]
CPU is: Intel64 Family 6 Model 61 Stepping 4, GenuineIntel
Total memory is:
TotalPhysicalMemory
17091084288
The disks that are installed and their freespace:
Caption FreeSpace Size
C: 212692340736 997923037184
All the KDV-PC IP addresses
IP Address: 192.168.56.1
IP Address: 169.254.45.2
IP Address: 169.254.126.64
IP Address: 192.168.159.1
IP Address: 192.168.181.1
IP Address: 192.168.1.40
IP Address: 127.0.0.1
What are the %name% used for in the script?
Answers will vary. These are environment variables which hold values set by the operating system.
Identify what the following commands do in the script:
echo: Displays on the screen whatever comes after it
findstr: Look for a string of characters.
netsh: Network shell allows to display and modify network settings.
ver: Gives the current OS version.
wmic: Windows management interface allows an administrator to view or modify settings.
Step 2: Create a Powershell ISE script.
a. Click Start, Search for PowerShell ISE and right-click the selection and click Run as an administrator.
b. Verify that you are in your home directory: PS C:\Users\YourUsername
c. To allow the script to run, enter Set-ExecutionPolicy RemoteSigned at the prompt. Click Yes to allow the script to run. The settings can be changed back to No after the script is complete.
PS C:\Users\YourUsername> Set-ExecutionPolicy RemoteSigned
d. Choose File -> New and create a new script.
e. Enter the following text into the Untitled.ps1 window and save it as info.ps1 in your home directory.
Write-Output "Computer name is:" get-content env:computername Write-Output "Windows version is:" (Get-WmiObject -class Win32_OperatingSystem).Caption Write-Output "CPU is:" Get-WmiObject Win32_Processor | findstr "Name" Write-Output "Total Memory is:" [Math]::Round((Get-WmiObject -Class win32_computersystem -ComputerName localhost).TotalPhysicalMemory/1Gb) Write-Output "The Disks that are installed and their freespace:" Get-WmiObject -Class Win32_logicaldisk -Filter "DriveType = '3'" Write-Output "IPv4 addresses" Get-NetIPAddress -AddressFamily IPv4 | Sort-Object -Property InterfaceIndex | Format-Table
Note: The command Get-NetIPAddress is not available in Windows 7.
Note: Within PowerShell ISE, you can press F1 or select Help > Windows PowerShell ISE Help to get more information.
f. To see the functions of each command, click Add-ons, verify that Command is checked. In the Command tab, enter the name of the command in the Name field. Select the desired command and click the ? for more information regarding the desired command.
In Windows 7, click Help > Select Windows PowerShell Help. Select Windows PowerShell Cmdlet Help Topics. Search for the desired command.
g. Enter .\info.ps1 at the PS prompt. Note: Make sure you are using the correct slash.
PS C:\Users\YourUsername> .\info.ps1
Question:
What is the output of the script?
Answers will vary.
PS C:\> .\info.ps1 Computer name is: KDV-PC Windows version is: Microsoft Windows 10 Education CPU is: Name: Intel(R) Core(TM) i5-5200U CPU @ 2.20GHz Total Memory is: 16 The Disks that are installed and their freespace: DeviceID : C: DriveType : 3 ProviderName : FreeSpace : 212635987968 Size : 997923037184 VolumeName : Windows IPv4 addresses ifIndex IPAddress PrefixLength PrefixOrigin SuffixOrigin AddressState PolicyStore ——- ——— ———— ———— ———— ———— ———– 1 127.0.0.1 8 WellKnown WellKnown Preferred ActiveStore 3 169.254.220.156 16 WellKnown Link Tentative ActiveStore 5 192.168.159.1 24 Manual Manual Preferred ActiveStore 7 169.254.160.146 16 WellKnown Link Tentative ActiveStore 11 192.168.56.1 24 Manual Manual Preferred ActiveStore 15 169.254.45.2 16 WellKnown Link Preferred ActiveStore 17 192.168.1.40 24 Dhcp Dhcp Preferred ActiveStore 24 169.254.2.220 16 WellKnown Link Tentative ActiveStore 25 169.254.126.36 16 WellKnown Link Tentative ActiveStore 29 169.254.18.19 16 WellKnown Link Tentative ActiveStore 39 192.168.181.1 24 Manual Manual Preferred ActiveStore 73 169.254.126.64 16 WellKnown Link Preferred ActiveStore
h. Compare the two scripts. Match the batch command to the PowerShell commands below:
| Windows Batch Command | PowerShell Command |
|---|---|
| echo Computer Name is: %computername% | Write-Output “Computer name is:” get-content env:computername |
| echo Windows version is: ver |
Write-Output “Windows version is:” (Get-WmiObject -class Win32_OperatingSystem).Caption |
| echo CPU is: %PROCESSOR_IDENTIFIER% b | Write-Output “CPU is:” Get-WmiObject Win32_Processor | findstr “Name” |
| echo Total memory is: | Write-Output “Total Memory is:” |
| wmic ComputerSystem get TotalPhysicalMemory | [Math]::Round((Get-WmiObject -Class win32_computersystem –ComputerName localhost).TotalPhysicalMemory/1Gb) |
| echo The disks that are installed and their freespace: | Write-Output “The Disks that are installed and their freespace:” |
| wmic logicaldisk get size,freespace,caption | Get-WmiObject -Class Win32_logicaldisk -Filter “DriveType = ‘3’” |
| echo All the %computername% IP addresses | Write-Output “IPv4 addresses” |
| netsh interface ip show address | findstr “IP Address” | Get-NetIPAddress –AddressFamily IPv4 | Sort-Object -Property InterfaceIndex | Format-Table |
Step 3: Create a BASH script.
A text editor is used to create an executable script. One of the text editor tools, vi, or the improved vi version, vim, is based on letter and number-based commands to modify text. For example, dd will delete the whole line on which the cursor is placed. 5dd would delete 5 lines. When vi is in command mode, input is interpreted as a command.
To enter insert mode at the current cursor position type i. To append text at the end of the current line, type a. To insert text on a new line below the current line, type o. Use the Esc key to exit out of insert mode to command mode.
To save a file in the vi editor use :w from command mode. To save and quit, type :wq. To quit without saving type :q!.
Depending on your version of Unix-like OS, you may find other text editor tool, such as nano, pico, and gedit. The text editing tools, such as vi, nano, and pico, are accessible through the command line; while the GUIbased text editors, like gedit, may be located via the application menu or the command line.
a. Start up a Linux computer or VM.
b. Use a text editor tool and create a file named info.sh in your home directory with the following text:
#!/bin/bash
echo "Computer name is: " $HOSTNAME
echo "Operating System is:"
cat /etc/os-release | grep PRETTY_NAME
echo "CPU is"
lscpu | grep "Model name:" | sed -r 's/Model name:\s{1,}//g'
echo "Total Memory is"
cat /proc/meminfo | grep "MemTotal"
echo "The disks that are installed and their freespace"
df -h
echo "All the" $HOSTNAME "IP addresses"
hostname -I
c. Open a terminal and navigate to your home directory. To make the script executable, enter chmod 755 info.sh at prompt.
d. At the prompt, enter ./info.sh to execute the script.
Questions:
What is the output of the script?
Answers will vary.
Computer name is: KDV-PC Operating System is: PRETTY_NAME=”Ubuntu 16.04.5 LTS” CPU is Intel(R) Core(TM) i5-5200U CPU @ 2.20GHz Total Memory is MemTotal: 16690512 kB The disks that are installed and their freespace Filesystem Size Used Avail Use% Mounted on rootfs 930G 732G 198G 79% / root 930G 732G 198G 79% /root home 930G 732G 198G 79% /home data 930G 732G 198G 79% /data cache 930G 732G 198G 79% /cache mnt 930G 732G 198G 79% /mnt none 930G 732G 198G 79% /dev none 930G 732G 198G 79% /run none 930G 732G 198G 79% /run/lock none 930G 732G 198G 79% /run/shm none 930G 732G 198G 79% /run/user C: 930G 732G 198G 79% /mnt/c All the KDV-PC IP addresses 192.168.56.1 192.168.159.1 192.168.181.1 169.254.45.2 169.254.126.64 192.168.1.40
What does the “#!/bin/bash” mean at the beginning of the script?
It tells the script which interpreter to use for the code.
What command would you use to learn more about the df and lscpu commands?
Use the man command to learn more. At the prompt, enter man df and man lscpu.