comptech101

CMD

Basic System Commands

• cls
  Clears the Command Prompt screen.
• exit
  Closes the Command Prompt window.
• echo Hello World
  Displays a message in the Command Prompt (outputs “Hello World”).
• time
  Displays or sets the system time. Example input: 12:30:00 to set the time.
• date
  Displays or sets the system date. Example input: 01-12-2024 to set the date.
• hostname
  Displays the name of the computer.
• ver
  Displays the version of Windows.
• systeminfo
  Displays detailed information about the system configuration.
• tasklist
  Lists all running processes.
• taskkill /IM notepad.exe
  Terminates the Notepad process.

File and Directory Management

• dir
  Lists the files and directories in the current folder.
• cd C:\Users\user1\Documents
  Changes to the specified directory.
• cd..
  Moves up one directory level.
• mkdir newFolder
  Creates a new directory named newFolder.
• rmdir newFolder
  Deletes the empty directory newFolder.
• del myfile.txt
  Deletes the file myfile.txt.
• copy C:\file1.txt D:\file2.txt
  Copies file1.txt from C: to D: as file2.txt.
• move C:\file1.txt D:\file2.txt
  Moves file1.txt from C: to D:.
• rename oldfile.txt newfile.txt
  Renames oldfile.txt to newfile.txt.
• attrib +r myfile.txt
  Sets the myfile.txt file to read-only.
• xcopy C:\Folder D:\Backup /s
  Copies the entire Folder from C: to D:\Backup (including subdirectories).
• robocopy C:\data D:\backup /e
  Copies files from C:\data to D:\backup, including all subdirectories and files.

Network Commands

• ping google.com
  Sends a network ping to google.com.
• ipconfig
  Displays the current IP configuration.
• ipconfig /all
  Displays detailed information about network interfaces.
• tracert google.com
  Traces the route packets take to google.com.
• netstat
  Displays active network connections and listening ports.
• nslookup google.com
  Looks up DNS information for google.com.
• net use X: \Server\SharedFolder
  Maps network share \\Server\SharedFolder to drive X:.

System Configuration and Maintenance

• chkdsk C:
  Checks and repairs errors on the C: drive.
• sfc /scannow
  Scans and repairs system files.
• diskpart
  Opens the disk partition tool.
• defrag C:
  Defragments the C: drive.
• shutdown /s /f /t 60
  Shuts down the computer in 60 seconds.
• shutdown /r /f /t 60
  Restarts the computer in 60 seconds.
• powercfg /hibernate off
  Disables hibernation on the system.
• msconfig
  Opens the System Configuration utility.
• regedit
  Opens the Registry Editor.

User Management

• net user
  Lists all user accounts on the computer.
• net user user1 password123 /add
  Adds a new user user1 with the password password123.
• net user user1 /delete
  Deletes the user account user1.
• net localgroup administrators user1 /add
  Adds user1 to the administrators group.
• net user user1 newpassword123
  Changes the password for user1 to newpassword123.

Drive and Disk Management

• diskpart
  Opens the disk partition utility.
• format D:
  Formats the D: drive (Warning: This deletes all data).
• chkdsk C: /f
  Fixes file system errors on the C: drive.

Environment and System Variables

• set
  Displays all environment variables.
• set PATH=C:\NewPath
  Sets the PATH environment variable to C:\NewPath.
• echo %PATH%
  Displays the current value of the PATH environment variable.

Advanced Commands

• find “error” log.txt
  Searches for the word error in log.txt.
• findstr “error” log.txt
  Searches for the word error in log.txt with more advanced options.
• assoc .txt=txtfile
  Associates the .txt file extension with the txtfile type.
• cipher /e C:\Data
  Encrypts the C:\Data folder.
• tasklist
  Lists all running processes on the system.
• taskkill /f /im notepad.exe
  Forcefully closes notepad.exe.
• schtasks /create /sc daily /tn “Backup” /tr “C:\Backup\backup.bat” /st 02:00
  Schedules a task to run backup.bat daily at 2:00 AM.

Help Commands

• help
  Displays a list of available commands.
• del /?
  Displays help information for the del command.

PowerShell

Basic System Commands

• Clear-Host
  Clears the PowerShell screen.
• Exit
  Closes the PowerShell window.
• Write-Host “Hello World”
  Displays a message in the PowerShell window (outputs “Hello World”).
• Get-Date
  Displays the current date and time.
• Set-Date “12/01/2024 14:30”
  Sets the system date and time to 12/01/2024 14:30.
• Get-Command
  Lists all available commands in PowerShell.
• Get-Help Get-Command
  Shows help information for the Get-Command command.
• Get-Process
  Lists all running processes.
• Stop-Process -Name notepad
  Terminates the notepad process.

File and Directory Management

• Get-ChildItem
  Lists the files and directories in the current directory.
• Set-Location C:\Users\user1\Documents
  Changes to the specified directory.
• New-Item -Path C:\ -Name “newFolder” -ItemType Directory
  Creates a new directory named newFolder in C:\.
• Remove-Item C:\newFolder
  Deletes the newFolder directory.
• Remove-Item C:\file1.txt
  Deletes the file1.txt file.
• Copy-Item C:\file1.txt -Destination D:\file2.txt
  Copies file1.txt from C: to D:\file2.txt.
• Move-Item C:\file1.txt -Destination D:\file2.txt
  Moves file1.txt from C: to D:\file2.txt.
• Rename-Item C:\file1.txt -NewName file2.txt
  Renames file1.txt to file2.txt.
• Get-Content C:\file1.txt
  Displays the contents of file1.txt.
• Set-Content C:\file1.txt “New content”
  Replaces the contents of file1.txt with “New content”.
• Add-Content C:\file1.txt “Additional content”
  Appends “Additional content” to file1.txt.
• Test-Path C:\file1.txt
  Checks if file1.txt exists in C: (returns True or False).

Network Commands

• Test-Connection google.com
  Sends a network ping to google.com.
• Get-NetIPAddress
  Displays IP address configuration information.
• Get-NetRoute
  Displays routing table information.
• Get-NetAdapter
  Lists all network adapters on the system.
• Set-NetIPAddress -InterfaceAlias “Ethernet” -IPAddress 192.168.1.100 -PrefixLength 24
  Sets a static IP address for the “Ethernet” interface.
• Get-DnsClientServerAddress
  Displays DNS server information for the system.

System Configuration and Maintenance

• Get-EventLog -LogName System
  Displays system event logs.
• Get-EventLog -LogName Application | Where-Object {$_.EntryType -eq “Error”}
  Displays error events from the Application log.
• Get-Service
  Lists all services running on the system.
• Start-Service -Name wuauserv
  Starts the Windows Update service.
• Stop-Service -Name wuauserv
  Stops the Windows Update service.
• Get-Command -Module Microsoft.PowerShell.Management
  Lists all commands available in the Microsoft.PowerShell.Management module.
• Get-Help Get-Command -Full
  Displays detailed help information for the Get-Command cmdlet.
• chkdsk C:
  Runs a disk check on the C: drive (run with admin privileges).
• sfc /scannow
  Scans and repairs system files (run with admin privileges).

User Management

• Get-LocalUser
  Lists all local user accounts.
• New-LocalUser -Name user1 -Password (ConvertTo-SecureString “password123” -AsPlainText -Force)
  Creates a new user user1 with the password password123.
• Remove-LocalUser -Name user1
  Deletes the user account user1.
• Add-LocalGroupMember -Group “Administrators” -Member user1
  Adds user1 to the Administrators group.
• Set-LocalUser -Name user1 -Password (ConvertTo-SecureString “newpassword123” -AsPlainText -Force)
  Changes the password for user1 to newpassword123.

Drive and Disk Management

• Get-PSDrive
  Lists all available drives.
• Get-Volume
  Lists all volumes on the system.
• Format-Volume -DriveLetter D -FileSystem NTFS -NewFileSystemLabel “NewVolume”
  Formats the D: drive with NTFS and labels it as “NewVolume”.
• Set-Partition -DriveLetter C -NewDriveLetter Z
  Changes the drive letter of C: to Z:.
• Resize-Partition -DriveLetter D -Size 100GB
  Resizes the D: partition to 100GB.

Environment and System Variables

• Get-EnvironmentVariable -Name PATH
  Displays the value of the PATH environment variable.
• Set-EnvironmentVariable -Name PATH -Value “C:\NewPath”
  Sets the PATH environment variable to C:\NewPath.
• [Environment]::SetEnvironmentVariable(“MyVar”, “MyValue”, “User”)
  Sets a user-level environment variable MyVar with value MyValue.
• [Environment]::GetEnvironmentVariable(“MyVar”, “User”)
  Retrieves the value of the user-level environment variable MyVar.

Advanced Commands

• Select-String “error” C:\log.txt
  Searches for the string “error” in the log.txt file.
• Get-Content C:\log.txt | Select-String “error”
  Filters the content of log.txt to display only lines containing “error”.
• Get-Command -Module Microsoft.PowerShell.Management | Export-Csv “commands.csv”
  Exports all available commands in the Microsoft.PowerShell.Management module to a CSV file.
• Start-Process notepad
  Launches Notepad.
• Stop-Process -Name notepad
  Stops the Notepad process.
• New-ScheduledTask -Action (New-ScheduledTaskAction -Execute “C:\Backup\backup.bat”) -Trigger (New-ScheduledTaskTrigger -At 2am -Daily) | Register-ScheduledTask -TaskName “BackupTask”
  Creates and schedules a daily backup task at 2 AM.

Help Commands

Get-Help
Lists all available help topics.

Get-Help Get-Command
Displays help information for the Get-Command cmdlet.

Get-Help -Name Get-Command -Full
Displays detailed help information for the Get-Command cmdlet.

Bash

Basic System Commands

• clear
  Clears the terminal screen.
• exit
  Closes the terminal window.
• echo “Hello World”
  Displays the message “Hello World” in the terminal.
• date
  Displays the current date and time.
• date “+%Y-%m-%d %H:%M:%S”
  Displays the current date and time in a custom format (e.g., 2024-12-01 14:30:00).
• hostname
  Displays the name of the current machine.
• uname -a
  Displays system information like kernel version and OS.
• uptime
  Displays how long the system has been running.
• whoami
  Displays the current logged-in user.

File and Directory Management

• ls
  Lists the files and directories in the current directory.
• ls -l
  Lists files in the current directory in long format (permissions, ownership, size).
• cd /home/user1/Documents
  Changes the current directory to /home/user1/Documents.
• cd ..
  Moves up one directory level.
• mkdir newfolder
  Creates a new directory named newfolder.
• rmdir newfolder
  Deletes the empty directory newfolder.
• rm file.txt
  Deletes the file file.txt.
• rm -r directory
  Recursively deletes a directory and its contents.
• cp file1.txt file2.txt
  Copies file1.txt to file2.txt.
• mv file1.txt /home/user1/Documents/
  Moves file1.txt to /home/user1/Documents/.
• rename file1.txt newfile.txt
  Renames file1.txt to newfile.txt.
• touch newfile.txt
  Creates an empty file named newfile.txt.
• cat file.txt
  Displays the contents of file.txt.
• more file.txt
  Displays the contents of file.txt one page at a time.
• head -n 10 file.txt
  Displays the first 10 lines of file.txt.
• tail -n 10 file.txt
  Displays the last 10 lines of file.txt.
• find /home/user1 -name “*.txt”
  Finds all .txt files in the /home/user1 directory.
• chmod 755 file.txt
  Changes the permissions of file.txt to rwxr-xr-x.
• chown user1:user1 file.txt
  Changes the owner and group of file.txt to user1.
• ln -s /path/to/original /path/to/symlink
  Creates a symbolic link.

Network Commands

• ping google.com
  Sends a network ping to google.com.
• ifconfig
  Displays network interface configuration (older systems, use ip instead).
• ip a
  Displays network interface configuration.
• ip link show
  Displays network interfaces and their states.
• netstat -tuln
  Lists all listening ports and their associated services.
• wget http://example.com/file.txt
  Downloads file.txt from example.com.
• curl -O http://example.com/file.txt
  Downloads file.txt from example.com using curl.
• ssh user1@hostname
  Connects to a remote server via SSH as user1.
• scp file.txt user1@hostname:/path/to/destination/
  Copies file.txt to a remote server using SCP.
• ftp ftp.example.com
  Connects to an FTP server.

Process Management

• ps aux
  Displays a list of all running processes.
• top
  Displays a dynamic, real-time view of system processes.
• kill 1234
  Terminates the process with PID 1234.
• killall firefox
  Terminates all processes named firefox.
• bg
  Resumes a suspended job in the background.
• fg
  Brings a job from the background to the foreground.
• jobs
  Lists all jobs running in the background or suspended.
• nice -n 10 command
  Runs command with a lower priority (nice value of 10).
• renice 10 -p 1234
  Changes the priority of the process with PID 1234 to 10.

User Management

• whoami
  Displays the current user.
• id user1
  Displays information about the user user1.
• adduser user1
  Adds a new user user1.
• userdel user1
  Deletes the user user1.
• usermod -aG sudo user1
  Adds user1 to the sudo group.
• passwd user1
  Changes the password for user1.
• su user1
  Switches to the user1 account.
• sudo command
  Runs a command with elevated privileges (as superuser).

System Management

• df -h
  Displays disk space usage in a human-readable format.
• du -sh directory
  Displays the total size of a directory (human-readable).
• free -h
  Displays memory usage (in human-readable format).
• top
  Displays a dynamic view of system processes.
• shutdown -h now
  Immediately shuts down the system.
• reboot
  Reboots the system.
• systemctl status apache2
  Checks the status of the apache2 service (or any other service).
• systemctl start apache2
  Starts the apache2 service.
• systemctl stop apache2
  Stops the apache2 service.
• systemctl enable apache2
  Enables the apache2 service to start at boot.
• systemctl disable apache2
  Disables the apache2 service from starting at boot.

Environment and System Variables

• echo $PATH
  Displays the current value of the PATH environment variable.
• export PATH=$PATH:/new/path
  Adds /new/path to the PATH environment variable.
• printenv
  Displays all environment variables.
• unset VAR_NAME
  Unsets (removes) the environment variable VAR_NAME.

File Permissions and Ownership

• chmod 755 file.txt
  Changes the permissions of file.txt to rwxr-xr-x.
• chown user1:user1 file.txt
  Changes the owner and group of file.txt to user1.
• chgrp group1 file.txt
  Changes the group ownership of file.txt to group1.

Search and Filtering

• grep “pattern” file.txt
  Searches for the string “pattern” in file.txt.
• grep -r “pattern” /home/user1/
  Recursively searches for the string “pattern” in the /home/user1 directory.
• find /home/user1 -name “*.txt”
  Finds all .txt files in /home/user1.
• sort file.txt
  Sorts the contents of file.txt alphabetically.
• cut -d ‘,’ -f 1 file.csv
  Extracts the first column of data from file.csv, assuming comma as delimiter.
• wc -l file.txt
  Counts the number of lines in file.txt.

Help Commands

command –help
Displays help information for a specific command (e.g., ls --help).

man command
Displays the manual for the specified command (e.g., man ls).