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System Administration Tools & Utilities Cheatsheet

A comprehensive cheat sheet covering essential system administration tools and utilities for managing and maintaining computer systems effectively, covering various operating systems and common tasks.

Process Management

Linux Process Commands

ps

Display a snapshot of the current processes.

top

Display dynamic real-time view of running processes.

htop

Interactive process viewer (needs installation).

kill PID

Terminate a process by its PID (Process ID).

killall process_name

Kill all processes by name.

pkill pattern

Kill processes matching a pattern.

nice -n priority command

Run a command with modified scheduling priority. (priority range: -20 to 19)

renice priority PID

Change the priority of an already running process.

Windows Task Manager

Access by pressing Ctrl + Shift + Esc.

Provides a GUI for viewing and managing processes, performance metrics, and startup applications.

Key features include:

  • Processes tab: Shows running applications and background processes.
  • Performance tab: Displays CPU, memory, disk, and network utilization.
  • Startup tab: Manages applications that run at startup.

Command-line equivalent: tasklist (lists processes) and taskkill (terminates processes).

Process Monitoring

vmstat

Virtual memory statistics - reports memory, swap, IO, system, and CPU activity.

iostat

Input/output statistics for block devices.

netstat or ss

Network statistics.

iotop

Monitor disk I/O usage by process. (needs installation)

iftop

Display bandwidth usage by host. (needs installation)

free -m

Display the amount of free and used memory in the system (in MB).

Networking Tools

Basic Networking Commands

ping hostname

Test network connectivity.

traceroute hostname

Trace the route packets take to a host.

netstat -tulnp

Display listening ports and associated processes (Linux).

ss -tulnp

Another tool to display listening ports and associated processes (Linux).

ip addr

Show network interfaces and IP addresses (Linux).

ifconfig

Configure network interface parameters (deprecated, but still used).

nslookup hostname

Query DNS servers to find IP addresses or other DNS records.

dig hostname

More advanced DNS lookup utility.

Windows Networking Commands

ipconfig

Display network configuration information.

ping hostname

Test network connectivity.

tracert hostname

Trace the route packets take to a host.

netstat -ano

Display active network connections and listening ports.

nslookup hostname

Query DNS servers.

pathping hostname

Provides information about network latency and packet loss at intermediate hops.

Network Monitoring Tools

Wireshark: A powerful network protocol analyzer. Captures and analyzes network traffic in real-time.

tcpdump: A command-line packet analyzer. Captures network traffic and saves it to a file for later analysis.

Nmap: A network scanner. Discovers hosts and services on a computer network by sending packets and analyzing the responses.

Nagios/Zabbix: Comprehensive network monitoring solutions. Monitor network services, servers, and other network devices.

Disk and File System Management

Linux Disk Commands

df -h

Display disk space usage in a human-readable format.

du -sh directory

Display the disk usage of a directory in a human-readable format.

lsblk

List block devices.

fdisk /dev/sda

Partition table manipulator (replace /dev/sda with the appropriate device).

mkfs.ext4 /dev/sda1

Create an ext4 filesystem on a partition (replace /dev/sda1 with the appropriate partition).

mount /dev/sda1 /mnt

Mount a filesystem (replace /dev/sda1 and /mnt with appropriate values).

umount /mnt

Unmount a filesystem.

fsck /dev/sda1

Check and repair a filesystem.

Windows Disk Management

Access via diskmgmt.msc or through the Control Panel.

Provides a GUI for managing disks, partitions, and volumes.

Key features include:

  • Creating and deleting partitions.
  • Formatting volumes.
  • Assigning drive letters.
  • Converting disks between basic and dynamic.

Command-line equivalent: diskpart (powerful disk partitioning tool).

File System Utilities

find /path -name filename

Find files by name in a directory.

grep pattern filename

Search for a pattern in a file.

tar -czvf archive.tar.gz directory

Create a compressed tar archive.

tar -xzvf archive.tar.gz

Extract a compressed tar archive.

rsync -av source destination

Synchronize files and directories. Can be used for backups.

chmod

Change file permissions.

chown

Change file owner and group.

User and Group Management

Linux User Management

useradd username

Create a new user.

passwd username

Change a user’s password.

usermod -aG groupname username

Add a user to a group.

userdel username

Delete a user.

id username

Show user’s ID and group memberships.

su username

Switch to another user.

sudo command

Execute a command as the superuser.

Linux Group Management

groupadd groupname

Create a new group.

groupmod -n new_groupname old_groupname

Rename a group.

groupdel groupname

Delete a group.

groups username

Display the groups a user belongs to.

getent group groupname

Get group information.

Windows User Management

GUI: Use the ‘Local Users and Groups’ management console (lusrmgr.msc). Command line:

net user username password /add - Adds a new user.
net localgroup groupname username /add - Adds a user to a local group.
net user username /delete - Deletes a user.

PowerShell:

New-LocalUser -Name "username" -Password "password" - Creates a new local user.
Add-LocalGroupMember -Group "groupname" -Member "username" - Adds a user to a local group.
Remove-LocalUser -Name "username" - Removes a local user.
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