Linux Command Guide
Here’s a list of some of the most useful Linux commands, organized by purpose, with descriptions and examples.
File and Directory Management
ls: Lists files and directories.Example:
ls -l(detailed view with permissions and sizes)
cd: Changes the current directory.Example:
cd /home/user/Documents
mkdir: Creates a new directory.Example:
mkdir new_folder
rm: Removes files or directories.Example:
rm file.txt(removes a file),rm -r folder_name(removes a directory and its contents)
cp: Copies files or directories.Example:
cp file.txt /backup/
mv: Moves or renames files or directories.Example:
mv old_name.txt new_name.txt
pwd: Prints the current directory path.Example:
pwd(outputs the current working directory)
File Viewing and Editing
cat: Displays file content.Example:
cat file.txt
less: Views file content one screen at a time.Example:
less longfile.txt
head: Displays the first few lines of a file.Example:
head -n 10 file.txt(shows the first 10 lines)
tail: Displays the last few lines of a file.Example:
tail -n 10 file.txt(shows the last 10 lines)
nano/vim: Text editors for editing files.Example:
nano file.txt(opens a file for editing using Nano)
File and Disk Management
df: Shows disk space usage.Example:
df -h(shows human-readable sizes)
du: Displays directory and file size.Example:
du -sh folder_name(shows size of a folder)
find: Searches for files and directories.Example:
find /home -name "file.txt"
locate: Quickly finds files using an indexed database.Example:
locate file.txt
stat: Displays detailed information about a file.Example:
stat file.txt
touch: Creates an empty file.Example:
touch newfile.txt
ln: Creates links to files.Example:
ln -s /path/to/file link_name
file: Determines file type.Example:
file file.txtRead more about
filehere.
System Information
top/htop: Displays running processes and system usage.Example:
top(real-time process monitoring)
uname: Displays system information.Example:
uname -a(detailed system info)
uptime: Shows how long the system has been running.Example:
uptime
free: Shows memory usage.Example:
free -h(human-readable format)
who: Lists users currently logged in.Example:
who
Networking
ping: Checks network connectivity to a host.Example:
ping google.com
curl/wget: Downloads files from the internet.Example:
curl -O http://example.com/file.txt
netstat: Displays network connections (deprecated, usess).Example:
netstat -tuln
ssh: Connects to a remote server via SSH.Example:
ssh user@192.168.1.1
File Permissions
chmod: Changes file permissions.Example:
chmod 755 file.txt
chown: Changes file ownership.Example:
chown user:group file.txt
ls -l: Shows detailed file permissions.Example:
ls -l
Process Management
ps: Displays running processes.Example:
ps aux(shows all processes)
kill: Terminates processes by ID.Example:
kill 1234(kills process with ID 1234)
jobs: Lists background jobs.Example:
jobs
bg/fg: Resumes background jobs in the foreground or background.Example:
fg %1(brings job 1 to the foreground)
Package Management (Varies by Distribution)
apt-get/apt: For Debian-based systems (e.g., Ubuntu).Example:
sudo apt update && sudo apt upgrade
yum/dnf: For Red Hat-based systems.Example:
sudo yum install package_name
pacman: For Arch-based systems.Example:
sudo pacman -S package_name
Archiving and Compression
tar: Archives files.Example:
tar -czvf archive.tar.gz folder_name
gzip/gunzip: Compresses or decompresses files.Example:
gzip file.txt,gunzip file.txt.gz
zip/unzip: Compresses or decompresses zip files.Example:
zip archive.zip file1 file2
Utilities
man: Displays the manual for a command.Example:
man ls
alias: Creates shortcuts for commands.Example:
alias ll='ls -la'
echo: Prints text to the terminal.Example:
echo "Hello, World!"
history: Shows the history of commands.Example:
history
grep: Searches for patterns in files.Example:
grep "error" log.txt
Peripheral and System Status Commands
Hardware Information
lscpu: Displays detailed CPU architecture information.Example:
lscpu
lsblk: Lists information about block devices (disks, partitions, etc.).Example:
lsblk
lspci: Lists all PCI devices and their details.Example:
lspciRead more about
lspcihere.
lsusb: Lists USB devices connected to the system.Example:
lsusb
lshw: Displays detailed information about the system's hardware (requires superuser privileges).Example:
sudo lshw
Disk and Storage
blkid: Displays UUIDs and labels of storage devices.Example:
blkid
fdisk: Partition table editor, useful for managing disk partitions.Example:
sudo fdisk /dev/sda
parted: Advanced disk partitioning tool.Example:
sudo parted /dev/sda
mount: Shows mounted filesystems.Example:
mount
umount: Unmounts mounted filesystems.Example:
umount /mnt
Memory and CPU
free: Shows available and used memory (RAM and swap).Example:
free -h
vmstat: Displays system performance statistics (memory, processes, I/O).Example:
vmstat 5
mpstat: Displays CPU usage statistics (from thesysstatpackage).Example:
mpstat
top/htop: Shows a real-time view of system processes and resource usage.Example:
top,htop
Network and Devices
ifconfig(deprecated, replaced byip): Displays network interfaces and their configurations.Example:
ifconfig
ip addr: Shows IP address configuration for network interfaces.Example:
ip addr
ip link: Displays information about network links/devices.Example:
ip link
ethtool: Displays or changes Ethernet device settings.Example:
ethtool eth0
iwconfig: Shows or configures wireless network interfaces.Example:
iwconfig wlan0
ping: Tests network connectivity to a host.Example:
ping google.com
ss: Displays active network connections and listening ports.Example:
ss -tuln
netstat: Shows network connections, routing tables, and interface statistics.Example:
netstat -rn
route: Displays or modifies the IP routing table.Example:
route -n
traceroute: Traces the routeExample:
traceroute google.com
mtr: Combinespingandtraceroutefunctionality.Example:
mtr google.com
arp: Displays or modifies the ARP cache.Example:
arp -a
hostname: Shows the system's hostname.Example:
hostname
dig: DNS lookup utility.Example:
dig example.com
nslookup: Another DNS lookup utility.Example:
nslookup example.com
System Logs and Status
dmesg: Displays kernel message buffer, useful for diagnosing hardware issues.Example:
dmesg | grep error
journalctl: Views systemd logs, including boot logs and service-related information.Example:
journalctl -xe
uptime: Shows how long the system has been running and the load average.Example:
uptime
sysctl: Views or modifies kernel parameters at runtime.Example:
sysctl -a
iostat: Displays CPU, I/O, and disk usage statistics (from thesysstatpackage).Example:
iostat
Battery and Power
acpi: Shows battery status and AC adapter information (requiresacpipackage).Example:
acpi
upower -i: Displays detailed battery information.Example:
upower -i /org/freedesktop/UPower/devices/battery_BAT0
powertop: Analyzes power usage and suggests optimizations.Example:
sudo powertop