Common Linux Commands

🗂️ 1. File and Directory Management

Command	Description
ls	List directory contents
cd	Change the current directory
pwd	Print working directory
mkdir	Create a new directory
rmdir	Remove an empty directory
rm	Remove files or directories
cp	Copy files or directories
mv	Move or rename files or directories
touch	Create an empty file
find	Search for files and directories
stat	Show detailed file info
tree	Display directory structure in a tree format
basename	Extract filename from path
dirname	Extract directory path from full path

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📄 2. File Viewing and Editing

Command	Description
cat	View file contents
less	View large files (scrollable)
more	View file contents one page at a time
head	Show first lines of a file
tail	Show last lines of a file
nano	Simple terminal-based text editor
vim	Advanced terminal-based text editor
vi	Traditional version of vim
gedit	GUI text editor (GNOME)
diff	Compare two files
cmp	Compare two files byte by byte

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📦 3. File Permissions and Ownership

Command	Description
chmod	Change file permissions
chown	Change file ownership
chgrp	Change group ownership
umask	Set default file permissions
ls -l	List file permissions and ownership

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📂 4. Archiving and Compression

Command	Description
tar	Archive files
zip / unzip	Compress/decompress ZIP archives
gzip / gunzip	Compress/decompress with Gzip
bzip2 / bunzip2	Compress/decompress with Bzip2
xz / unxz	Compress/decompress with XZ
7z	7-Zip compression (if installed)

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⚙️ 5. System Information

Command	Description
uname -a	Show system information
hostname	Show or set hostname
uptime	Show how long the system has been running
top	Display real-time processes
htop	Interactive process viewer (if installed)
whoami	Show current user
id	Show user and group ID
df -h	Show disk usage
du -sh	Show directory size
free -h	Show memory usage
vmstat	Show system performance
lscpu	Show CPU info
lsblk	List block devices
lspci	List PCI devices
lsusb	List USB devices

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🔧 6. Process Management

Command	Description
ps	Show running processes
top	Real-time process viewer
htop	Enhanced version of top
kill	Kill a process by PID
killall	Kill processes by name
nice / renice	Set process priority
jobs	List background jobs
fg	Bring job to foreground
bg	Resume job in background

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🌐 7. Networking

Command	Description
ip a	Show IP addresses
ifconfig	Show network interfaces (older tool)
ping	Test network connectivity
traceroute	Trace the route to a host
netstat	Network stats (deprecated)
ss	Modern replacement for netstat
curl	Transfer data from/to a server
wget	Download files from the web
dig	DNS lookup
nslookup	Query Internet name servers
host	DNS lookup tool
scp	Secure file copy between systems
rsync	Remote/local file synchronization

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🔐 8. User Management

Command	Description
adduser / useradd	Create a new user
passwd	Change user password
deluser / userdel	Delete a user
groupadd	Add new group
groupdel	Delete a group
usermod	Modify a user
groups	Show user groups
su	Switch user
sudo	Run command as superuser

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📜 9. Package Management

🔹 Varies by distribution. Here are the main tools per distro:

For Debian/Ubuntu:

Command	Description
apt update	Update package lists
apt upgrade	Upgrade installed packages
apt install <pkg>	Install a package
apt remove <pkg>	Remove a package
dpkg -i <pkg.deb>	Install .deb file

For RHEL/CentOS/Fedora:

Command	Description
yum install <pkg>	Install package (older systems)
dnf install <pkg>	Install package (newer systems)
rpm -i <pkg.rpm>	Install .rpm file

For Arch Linux:

Command	Description
pacman -Syu	Update and upgrade
pacman -S <pkg>	Install package

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⌨️ 10. Shell and Scripting

Command	Description
echo	Print to terminal
read	Take input from user
alias	Create command shortcut
unalias	Remove alias
which	Show command path
whereis	Locate binary/source/man page
man	Show manual pages
bash	Start a new shell session
sh	Bourne shell
history	Show command history
source	Run commands from a script in the current shell

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🧪 11. Disk and Filesystem

Command	Description
mount	Mount a device
umount	Unmount a device
fsck	Filesystem check
mkfs	Create a new filesystem
blkid	Locate/identify devices
fdisk	Partition a disk
parted	Disk partitioning tool

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🧼 12. System Maintenance

Command	Description
reboot	Reboot system
shutdown	Shutdown system
systemctl	Control systemd services
journalctl	View logs from systemd
cron / crontab	Schedule tasks
at	Run tasks at a specified time
logrotate	Rotate log files

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🧙‍♂️ 13. Miscellaneous

Command	Description
date	Show or set the date/time
cal	Display calendar
env	Show environment variables
export	Set environment variable
time	Measure execution time
yes	Output a string repeatedly
sleep	Pause for seconds
watch	Run command at intervals
alias	Create command shortcuts

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