Linux Command Cheat Sheet: File, Directory, Process, Network, and System Management

File and Directory Management

pwd – display the current directory.

ls [-l] – list directory contents; -l shows detailed information.

cd [directory] – change to the specified directory.

mkdir [-p] directory – create a directory; -p creates parent directories as needed.

rmdir directory – remove an empty directory.

rm [-rf] file_or_directory – delete files or directories; -r recursive, -f force.

File Operations

touch filename – create an empty file or update its timestamp.

cp source destination – copy files or directories.

mv source destination – move or rename files or directories.

cat filename – display the entire contents of a file.

head filename – show the beginning of a file.

tail [-n] filename – show the end of a file; -n specifies the number of lines.

less/more filename – view file contents page by page.

Permission Management

ls -l – view file and directory permissions.

chmod permissions file_or_directory – change permissions (e.g., chmod 755 file.txt ).

chown user:group file_or_directory – change ownership.

Search and Find

find [path] [criteria] – locate files (e.g., find . -name "test*.txt" ).

grep "keyword" filename or grep -r "keyword" directory – search file contents; -r recursive.

Process Management

ps aux – list currently running processes.

kill [signal] PID or pkill process_name – terminate processes.

pgrep process_name – find process IDs by name.

Network Related

ifconfig or ip addr show – display IP addresses.

ping target_address – test network connectivity.

netstat -tuln or ss -tuln – show listening ports.

System Information and Resource Monitoring

top or htop – view CPU and memory usage.

df -h – display disk space usage per partition.

du -sh * – show size of each file and directory in the current folder.

System and Hardware Information

uname -a – show kernel and system version.

uptime – display how long the system has been running.

lshw or dmidecode – detailed hardware information.

Log Viewing and Management

tail -f logfile – follow a log file in real time.

ls -lt – list files sorted by most recent modification.

Text Processing and Editing

sed -i 's/old/new/g' filename – replace text in a file in place.

awk – powerful column‑oriented text processing tool.

Package Management (Debian/Ubuntu)

apt-get install package_name – install a package.

apt-get update – refresh the package list.

apt-get upgrade – upgrade installed packages.

Package Management (RPM/CentOS)

yum install package_name – install a package.

yum check-update – check for available updates.

yum upgrade – upgrade installed packages.