Linux Command Cheat Sheet

A running reference of the Linux commands I find myself using or looking up most often — organized by category. Covers everyday file navigation, text processing, user and permission management, and networking. Commands are written for a typical Bash environment on Debian/Ubuntu or RHEL/Rocky; most will work on any modern Linux distro.

//Navigation & Files22 commands

CommandWhat it does

pwdPrint the full path of the current working directory
lsList files and directories in the current directory
ls -laList all files (including hidden) with detailed info
cd <dir>Change into a directory
cd ..Move up one directory level
cd ~Go to your home directory
mkdir <dir>Create a new directory
mkdir -p <path>Create a directory and any missing parent directories
touch <file>Create an empty file, or update its timestamp if it exists
cp <src> <dest>Copy a file from source to destination
cp -r <src> <dest>Copy a directory and all its contents recursively
mv <src> <dest>Move or rename a file or directory
rm <file>Delete a file permanently
rm -rf <dir>Delete a directory and everything in it — no confirmation
find <path> -name <pattern>Search for files matching a name pattern
find . -type f -mtime -7Find files modified in the last 7 days
locate <name>Fast file search using an indexed database
ln -s <target> <link>Create a symbolic (soft) link to a file or directory
stat <file>Show detailed metadata about a file
du -sh <dir>Show total disk usage of a directory in human-readable form
df -hShow available disk space on all mounted filesystems
treeDisplay directory structure as a visual tree

//Text & Search22 commands

CommandWhat it does

cat <file>Print the contents of a file to the terminal
less <file>View a file page by page — press q to quit
head -n <N> <file>Show the first N lines of a file
tail -n <N> <file>Show the last N lines of a file
tail -f <file>Stream a file as it grows — ideal for watching logs
grep <pattern> <file>Search for lines matching a pattern in a file
grep -r <pattern> <dir>Search for a pattern recursively across all files in a directory
grep -i <pattern>Case-insensitive pattern search
grep -v <pattern>Show lines that do NOT match the pattern
sed 's/old/new/g' <file>Replace every occurrence of old with new in a file (output only)
sed -i 's/old/new/g' <file>Replace text inside a file in place
awk '{print $1}' <file>Print the first field (column) of each line
cut -d: -f1 <file>Extract the first field using : as the delimiter
sort <file>Sort lines in a file alphabetically
sort -n <file>Sort lines numerically
uniqRemove consecutive duplicate lines (pipe from sort first)
sort | uniq -cSort and count how many times each unique line appears
wc -l <file>Count the number of lines in a file
wc -w <file>Count the number of words in a file
diff <file1> <file2>Show line-by-line differences between two files
echo <text>Print text to the terminal or redirect it into a file
tee <file>Write stdin to both stdout and a file simultaneously

//Permissions & Users22 commands

CommandWhat it does

whoamiPrint the name of the currently logged-in user
idShow your user ID, primary group ID, and all group memberships
groupsList all groups the current user belongs to
sudo <command>Run a command with superuser (root) privileges
sudo -iOpen an interactive root shell
su - <user>Switch to another user account
chmod 755 <file>Set rwxr-xr-x permissions — owner can write, others can read and execute
chmod +x <file>Make a file executable
chmod -R 644 <dir>Apply permissions recursively to all files in a directory
chown <user> <file>Change the owner of a file
chown <user>:<group> <file>Change both the owner and group of a file
chown -R <user>:<group> <dir>Change owner and group recursively
useradd -m <user>Create a new user with a home directory
userdel -r <user>Delete a user and remove their home directory
usermod -aG <group> <user>Add a user to a group without removing existing groups
passwd <user>Set or change a user password
groupadd <group>Create a new group
visudoSafely edit the sudoers file with syntax validation
lastShow recent login history for all users
umask 022Set the default permissions mask for newly created files
ls -l <file>View the permission string, owner, and group of a file
stat <file>Show full permission details including octal notation

//Networking22 commands

CommandWhat it does

ip addr showShow all network interfaces and their IP addresses
ip route showDisplay the routing table
ip link set <iface> upBring a network interface up
ping <host>Test basic network connectivity to a host
ping -c 4 <host>Send exactly 4 ping packets then stop
traceroute <host>Show the route packets take to reach a host
ss -tulnpShow all listening TCP/UDP ports and the process using each
ss -sShow a summary of socket statistics
curl <url>Fetch content from a URL
curl -I <url>Fetch only the HTTP response headers from a URL
curl -O <url>Download a file, preserving the remote filename
wget <url>Download a file from a URL
wget -r <url>Recursively download an entire website
ssh <user>@<host>Open a secure shell session on a remote host
ssh -i <key> <user>@<host>Connect to a remote host using a private key file
scp <file> <user>@<host>:<path>Securely copy a file to a remote host
scp -r <dir> <user>@<host>:<path>Securely copy a directory to a remote host
dig <domain>Perform a full DNS lookup for a domain
dig +short <domain>Quick DNS lookup — returns only the answer
nslookup <domain>Query a DNS server interactively
nmap -sV <host>Scan a host and detect service versions on open ports
ufw statusShow the current firewall rules and status

// A Note on Usage

Commands marked with angle brackets like <file> expect you to substitute your actual value. Commands that destructively modify data (rm -rf, sed -i) should be tested with a dry run or on a copy first. When in doubt, man <command> opens the full manual page.

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This is a personal reference, not a comprehensive manual. If you spot an error or a command that should be here, reach out via the contact page.