Common Most Useful Terminal Commands

User Information

Show the current logged-in user.

whoami

Show the User details.

finger <username>

Date and Time

Display the current date and time.

date

File System Navigation

Command	Description
pwd	Print working directory
ls	List directory contents
ls -a	List all contents including hidden files
ls -l	List contents with detailed information
cd	Change to home directory
cd [dirname]	Change to specific directory
cd ..	Change to parent directory
find [dirtosearch] -name [filename]	Find a file or directory

Opening Files or Folders

Open files or directories in GUI.

• Mac: open [dirname]
• Windows: start [dirname]
• Linux: xdg-open [dirname]

Modifying Files & Directories

Command	Description
mkdir [dirname]	Make directory
touch [filename]	Create file
rm [filename]	Remove file
rm -r [dirname]	Remove directory
cp [filename] [dirname]	Copy file
mv [filename] [dirname]	Move file
mv [filename] [filename]	Rename file or directory

Output Redirection

Create a new file with output.

> [filename]

Concatenate Files

View, create, or append files.

cat [filename]
cat > [filename]
cat >> [filename]

Viewing Files

View file contents with scrolling.

less [filename]

Exit with q.

Display Text

Display messages or create/write files.

echo "Hello World"
echo "Hello World" > [filename]
echo "Hello World" >> [filename]

Text Editor

Edit files with Nano.

nano [filename]

Exit with Ctrl + X, then Y to save or N to discard.

Head and Tail

Display the beginning or end of files.

head [filename]
head -n 5 [filename]
tail [filename]
tail -n 5 [filename]

Search Text

Search for patterns in files.

grep [searchterm] [filename]

Find Files

Locate files and directories.

find [dirname] -name [filename]
find . -empty
find . -name "file-*" -delete

Piping

Redirect output to another command or file.

find . -name "file-0*" > output.txt

Symlinks

Create shortcuts to files or directories.

ln -s [filename] [symlinkname]
rm [symlinkname]

For Windows:

mklink [symlinkname] [filename]

File Compression

Compress or extract files with tar.

Command	Description
tar czvf [dirname].tar.gz [dirname]	Create tarball
tar tzvf [dirname]	See contents of tarball
tar xzvf [dirname].tar.gz	Extract tarball

Networking Commands

Command	Description
ifconfig	Display network configuration
ip addr show	Display IP addresses and network interfaces
ping [hostname]	Check connectivity to a host
traceroute [hostname]	Trace the route packets take to a network host
nslookup [hostname]	Query the DNS for information about a domain
dig [domain]	Detailed DNS query
netstat	Network statistics
curl [url]	Transfer data from or to a server
wget [url]	Download files from the web

System Monitoring

Command	Description
top	Display active processes
htop	Interactive process viewer
ps	Display information about active processes
df	Report file system disk space usage
du	Estimate file space usage
free	Display memory usage
uname -a	Display system information

Disk Usage

Command	Description
df -h	Show disk usage in human-readable format
du -sh [dirname]	Show disk usage for a directory
du -shl *	Show disk usage for all items in a directory

Package Management (Linux)

Command	Description
apt-get update	Update package lists (Debian/Ubuntu)
apt-get upgrade	Upgrade installed packages (Debian/Ubuntu)
yum update	Update packages (RedHat/CentOS)
yum upgrade	Upgrade packages (RedHat/CentOS)

System Information

Command	Description
uname -r	Show kernel version
lsb_release -a	Show Linux distribution information
hostnamectl	Query and change the system hostname

Permissions

Command	Description
chmod [options] [filename]	Change file mode (permissions)
chown [owner]:[group] [file]	Change file owner and group
sudo [command]	Execute a command as another user
getfacl	Easy Permission Read(File Access Control)