Linux Commands | The Complete Comprehensive List

Linux Commands | The Complete Comprehensive List

Computer interface graphic showcasing Linux Commands Complete List offering a comprehensive overview of Linux commands

Here at IOFLOOD, a solid understanding of Linux commands is crucial for maintaining the health of our customer’s dedicated servers. Drawing from our years of experience in managing servers and linux systems, we have crafted this complete Linux commands list. Our hope is that these insights can prove a useful resource for our customers as well as other Linux users.

In this Linux Commands Reference Guide, each command is presented in organized tables, accompanied by a brief explanation and a sample usage syntax. For those looking to dive deeper, many commands also include links to related articles covering installation and usage. These extra resources will be invaluable for mastering the usage of each command.

Whether you’re looking to troubleshoot a problem, optimize your workflow, or explore new options, this reference is your compass in the Linux universe. Let’s get started and unlock the full potential of Linux!

System Information and Management

In this section, you’ll find Linux commands that help you retrieve information about processes, environment variables, system configuration, hardware details, and system uptime and allow you to monitor and manage system resources.

CommandExplanationExample Usage
apropos (Installation)Searches the man pages.apropos keyword
arch (Installation)Displays the machine architecture.arch
chroot (Installation)Changes the root directory.sudo chroot /new/root
env (Installation)Displays, sets, or removes environment variables.env
free (Installation)Displays the total amount of free and used memory in the system.free -m
historyDisplays the command history.history
hostname (Installation)Shows or sets the system’s host name.hostname
i3 (Installation)A tiling window manager, completely written from scratch.i3
lsblk (Installation)Lists information about block devices.lsblk
lspci (Installation)Lists all PCI devices.lspci
man (Installation)Displays the manual for a command.man ls
modprobe (Installation)Adds or removes modules from the Linux kernel.modprobe module_name
neofetch (Installation)Displays system information in an aesthetic way.neofetch
reboot (Installation)Restarts the system.reboot
stat (Installation)Displays file or filesystem status.stat filename
strace (Installation)Traces system calls and signals.strace -p PID
sysctl (Installation)Configures kernel parameters at runtime.sysctl -p
systemctl (Installation)Controls the systemd system and service manager.systemctl status service_name
systemd (Installation)System and service manager for Linux.systemd
tee (Installation)Reads from standard input and writes to standard output and files.echo "Hello" | tee file.txt
tty (Installation)Prints the file name of the terminal connected to standard input.tty
uname (Installation)Shows system information.uname -a
uptime (Installation)Tells how long the system has been running.uptime

File and Directory Operations

In this section, you’ll discover fundamental Linux commands for working with files and directories. These commands will enable you to create, modify, manage, and navigate through files and directories efficiently.

CommandExplanationExample Usage
cdChanges the current directory.cd /var/log
chmod (Installation)Changes the file mode (permissions).chmod 755 script.sh
cp (Installation)Copies files and directories.cp file.txt /tmp/
diff (Installation)Compares files line by line.diff file1 file2
dos2unix (Installation)Converts text files from DOS to Unix format.dos2unix file.txt
file (Installation)Determines file type.file example.txt
find (Installation)Searches for files in a directory hierarchy.find / -name "example.txt"
gunzip (Installation)Decompresses gzipped files.gunzip file.gz
gzip (Installation)Compresses or decompresses files.gzip file
ln (Installation)Creates a link to a file or directory.ln -s /path/to/file /path/to/link
locate (Installation)Finds files by name quickly using a database.locate example.txt
logrotate (Installation)Rotates, compresses, and mails system logs.logrotate config_file
ls (Installation)Lists the contents of a directory.ls -l /home/user
lsof (Installation)Lists open files and the processes that opened them.lsof
mkdir (Installation)Creates a new directory.mkdir /tmp/newdir
mv (Installation)Moves or renames files and directories.mv file.txt /tmp/newname.txt
rm (Installation)Removes files or directories.rm -rf /tmp/oldfiles
rmdir (Installation)Removes empty directories.rmdir /tmp/emptydir
tar (Installation)Archives files into a tarball or extracts them.tar -czvf archive.tar.gz /path/to/dir
touch (Installation)Creates a new empty file or updates the timestamp of an existing file.touch /tmp/newfile.txt
unrar (Installation)Extracts files from RAR archives.unrar x archive.rar
unzip (Installation)Extracts files from a zip archive.unzip archive.zip
whereis (Installation)Locates the binary, source, and manual pages for a command.whereis ls
whichLocates the full path of shell commands.which ls

Package Management

In this section, you’ll explore key Linux commands that streamline the installation, update, and removal of software packages on your system and are integral to managing software packages efficiently. Whether you’re installing new applications, updating existing packages, or removing unwanted software, these commands provide the necessary tools to maintain a well-managed Linux system.

CommandExplanationExample Usage
apt-getPackage management system for Debian/Ubuntu.sudo apt-get update && sudo apt-get upgrade
aptitude (Installation)Alternative package manager for Debian/Ubuntu, with a UI and more features.sudo aptitude search package_name
dnf (Installation)Fedora’s package manager since Fedora 22, replacing yum.sudo dnf update
dpkg (Installation)Debian package manager, used to install, remove, and provide information about .deb packages.dpkg -i package_file.deb
git (Installation)Distributed version control system used for source code management.git clone https://github.com/u/repo.git
rpm (Installation)RPM Package Manager, used in Red Hat, Fedora, and others.rpm -ivh package_file.rpm
yum (Installation)Package manager for Red Hat/Fedora before Fedora 22, manages RPM packages.yum install package_name

Networking

In the “Networking” section, you’ll explore Linux commands that deal with network monitoring, configuration, and troubleshooting. These commands are invaluable tools for managing network operations effectively on your Linux system, diagnosing network problems, or fetching data from remote servers.

CommandExplanationExample Usage
arp (Installation)Manipulates the ARP cache.arp -a
curl (Installation)Transfers data from or to a server, using one of the supported protocols.curl -O http://example.com/file
dig (Installation)Queries DNS servers for information.dig example.com
ethtool (Installation)Displays or changes Ethernet card settings.ethtool eth0
ftp (Installation)Standard network protocol for transferring files.ftp ftp.example.com
host (Installation)DNS lookup utility.host example.com
ifconfig (Installation)Configures and displays network interface parameters.ifconfig eth0
ip (Installation)Manipulates and displays IP networking information.ip addr show
iptables (Installation)Administration tool for IPv4 packet filtering and NAT.iptables -L
mtr (Installation)Combines the functionality of the ‘traceroute’ and ‘ping’ programs.mtr example.com
nc or netcat (Installation)Networking utility for reading from and writing to network connections.nc example.com 80 or netcat example.com 80
ncat (Installation)Improved re-implementation of the Unix netcat utility.ncat example.com 80
netstat (Installation)Displays network connections, routing tables, interface statistics, masquerade connections, and multicast memberships.netstat -tuln
nmcli (Installation)Command-line tool for controlling NetworkManager.nmcli d
nmap (Installation)Network exploration tool and security / port scanner.nmap -A example.com
nmtui (Installation)Text user interface for NetworkManager.nmtui
nslookup (Installation)Queries Internet domain name servers.nslookup example.com
ping (Installation)Sends ICMP ECHO_REQUEST packets to network hosts.ping example.com
route (Installation)Shows or manipulates the IP routing table.route -n
scp (Installation)Secure copy (remote file copy program).scp localfile user@remote:/remotepath
sftp (Installation)Secure File Transfer Protocol.sftp user@host
ssh (Installation)Secure Shell, a program to log into another computer over a network.ssh [email protected]
ss (Installation)Utility to investigate sockets.ss -tulw
tcpdump (Installation)Powerful command-line packet analyzer.tcpdump -i eth0
telnet (Installation)User command and TCP/IP protocol for accessing remote computers.telnet example.com 23
traceroute (Installation)Prints the route packets take to network host.traceroute example.com
wget (Installation)Non-interactive network downloader.wget http://example.com/file

User and Group Management

In this section, you’ll explore Linux commands focused on managing users and groups, providing tools for user account administration and permissions management. These commands enable you to create new user accounts, modify user attributes, manage user privileges, create groups, and change group ownership of files and directories. and should generally offer essential utilities for user and group management tasks.

CommandExplanationExample Usage
adduser (Installation)Interactive script to add a new user.adduser newusername
chage (Installation)Changes the number of days between password changes and the date of the last password change.chage -d 0 username
chgrp (Installation)Changes group ownership.chgrp newgroup file
chown (Installation)Changes file owner and group.chown newowner:newgroup file
groupadd (Installation)Adds a new group to the system.groupadd newgroup
passwd (Installation)Updates a user’s authentication tokens/password.passwd username
su (Installation)Substitute user identity.su - username
sudo (Installation)Executes a command as another user, according to the security policy.sudo apt-get update
useradd (Installation)Low-level utility for adding users.useradd -m newusername
usermod (Installation)Modifies a user account.usermod -aG sudo newusername

Process Management

In the “Process Management” section, you’ll discover Linux commands dedicated to managing processes, offering tools for controlling and monitoring running programs effectively. These commands, including atop, pkill, nohup, and kill, enable you to monitor process activity, terminate processes, run processes in the background, and schedule tasks. Whether you’re analyzing process performance, stopping specific processes, running processes in the background, or managing process termination, these commands provide essential utilities for process management tasks on your Linux system.

CommandExplanationExample Usage
atop (Installation)Advanced system and process monitor.atop
fgMoves jobs to the foreground.fg %jobnumber
kill (Installation)Sends a signal to a process, typically to stop the process.kill PID
killall (Installation)Kills processes by name (as opposed to PID).killall processname
nohup (Installation)Runs a command immune to hangups, with output to a non-tty.nohup command &
pgrep (Installation)Looks up processes based on name and other attributes.pgrep -u username
pkill (Installation)Sends signals to processes based on name and other attributes.pkill processname
ps (Installation)Displays information about active processes.ps aux

Text Processing

In “Text Processing”, you’ll explore a collection of Linux commands designed for manipulating and processing text data, such as: awk, uniq, nano, and more. Whether you need to extract specific fields, remove duplicate lines, sort data alphabetically or numerically, search for patterns, edit text files, or view text content, these commands will be your go-to.

CommandExplanationExample Usage
awk (Installation)Pattern scanning and processing language.awk '/pattern/ {print $0}' file.txt
cat (Installation)Concatenates and displays files.cat file.txt
cut (Installation)Removes sections from each line of files.cut -d':' -f1 /etc/passwd
echo (Installation)Displays a line of text.echo "Hello, World!"
emacs (Installation)Extensible, customizable text editor.emacs file.txt
grep (Installation)Searches for patterns in files.grep 'pattern' file.txt
head (Installation)Displays the first part of files.head -n 5 file.txt
less (Installation)Similar to more, but allows backward movement in the file as well as forward movement.less /var/log/syslog
more (Installation)Views file contents page by page.more /var/log/syslog
nano (Installation)Easy to use text editor.nano file.txt
paste (Installation)Merges lines of files.paste file1.txt file2.txt
sed (Installation)Stream editor for filtering and transforming text.sed 's/original/replacement/' file.txt
sort (Installation)Sorts lines of text files.sort file.txt
tail (Installation)Displays the last part of files.tail -n 5 file.txt
uniq (Installation)Reports or omits repeated lines.uniq file.txt
vim (Installation)Highly configurable text editor.vim file.txt
wc (Installation)Prints newline, word, and byte counts for each file.wc -l file.txt

Disk and File System Management

In this section, you’ll encounter Linux commands focused on managing disks and file systems, providing tools for storage management and partitioning. Whether you’re analyzing disk space usage, managing mounted filesystems, mounting external storage devices, or resizing partitions, these commands offer essential utilities for disk and file system management in Linux.

CommandExplanationExample Usage
dd (Installation)Converts and copies a file, can be used for creating disk images.sudo dd if=/dev/sda of=/path/to/backup.img
dfDisplays the amount of disk space used and available on filesystems.df -h
du (Installation)Estimates file space usage.du -sh /path/to/directory
fdisk (Installation)Partition table manipulator for Linux.sudo fdisk /dev/sda
gparted (Installation)GNOME partition editor for manipulating disk partitions graphically.gparted (GUI application)
lsblk (Installation)Lists information about all available or specified block devices.lsblk
mkfs (Installation)Builds a Linux filesystem on a device, usually a partition.sudo mkfs.ext4 /dev/sda1
mount (Installation)Mounts a filesystem on a directory.sudo mount /dev/sda1 /mnt
umount (Installation)Unmounts a mounted filesystem.sudo umount /mnt

System Monitoring and Performance

In this section, you’ll explore Linux commands, including free, top, journalctl, and htop, that provide real-time insights into memory usage, CPU utilization, system processes, and system logs. These commands offer valuable tools for optimizing system performance and ensuring smooth operation on your Linux system.

CommandExplanationExample Usage
dmesg (Installation)Prints or controls the kernel ring buffer.dmesg | grep USB
free (Installation)Displays the amount of free and used memory in the system.free -m
htop (Installation)An interactive process viewer, considered an upgrade to top.htop
journalctl (Installation)Queries and displays messages from the journal.journalctl -p err -b
sar (Installation)Collects, reports, or saves system activity information.sar -u 1 3
top (Installation)Displays a dynamic real-time view of running processes.top

Scripting and Automation

In the “Scripting and Automation” section, you’ll delve into Linux commands great for scripting and automating tasks. Whether you’re creating custom aliases, processing command outputs, implementing conditional statements, scheduling cron jobs, or writing Bash scripts, these commands are indispensable for scripting and automation.

CommandExplanationExample Usage
alias (Installation)Creates an alias for a commandalias ll='ls -l'
ansibleAutomates cloud provisioning, configuration management, and application deployments.ansible-playbook playbook.yml
bash (Installation)GNU Bourne-Again SHell, a sh-compatible command language interpreter.bash script.sh
caseConditionally executes a block of commands.case $var in pattern) commands ;; esac
crontab (Installation)Schedules scripts or commands to run at specified times and dates.crontab -e
expect (Installation)Automates interactive applications according to a script.expect script.exp
forIterates over a list of items in shell scripts.for i in {1..5}; do echo "Welcome $i"; done
functionDefines a set of commands as a function.function name { commands }
ifExecutes commands based on conditional execution.if [ condition ]; then commands; fi
make (Installation)Automates the build process of projects.make
puppet-agentPuppet Agent is responsible for managing the configuration of nodes (client machines) in a Puppet setup.sudo puppet agent -t
puppet-masterPuppet Master is the central server that stores and serves Puppet configurations to Puppet Agents.sudo systemctl status puppet
whileExecutes commands as long as the condition is true.while [ condition ]; do commands; done
xargs (Installation)Builds and execute command lines from standard input.find . -type f -name '*.txt' | xargs grep 'searchstring'

Security and Encryption

In this section, you’ll explore Linux commands for enhancing system security and implementing encryption measures. These commands are great tools for safeguarding your system from unauthorized access, encrypting communications, generating secure keys, or managing firewall settings.

CommandExplanationExample Usage
fail2ban (Installation)Scans log files and bans IPs that show malicious signs.fail2ban-client status sshd
firewalld (Installation)A firewall management tool for dynamically managing a firewall with support for network/firewall zones.firewall-cmd --state
gpg (Installation)GNU Privacy Guard, a tool for secure communication and data storage.gpg --gen-key
openssl (Installation)Toolkit for the Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols.openssl genrsa -out private.key 2048
ssh-keygen (Installation)Generates, manages, and converts authentication keys for ssh.ssh-keygen -t rsa -b 4096
ufw (Installation)Uncomplicated Firewall, a user-friendly front-end for managing iptables firewall rules.ufw allow from 192.168.1.0/24 to any port 22

Miscellaneous Utilities

In this final section, you’ll encounter various Linux commands that offer a range of functionalities beyond specific categories. These commands provide diverse utilities for tasks like displaying messages, monitoring command output, managing terminal sessions, and manipulating date and time information.

CommandExplanationExample Usage
bc (Installation)An arbitrary precision calculator language.echo "sqrt(25)" | bc -l
date (Installation)Displays or sets the system date and time.date "+%Y-%m-%d %H:%M:%S"
rsync (Installation)Fast and versatile file copying tool that can synchronize files and directories between two locations over a network.rsync -av source/ destination/
screen (Installation)Allows you to manage multiple terminal sessions inside a single window.screen -S session_name
tmux (Installation)A terminal multiplexer, it enables a number of terminals to be created, accessed, and controlled from a single screen.tmux new -s session_name
watch (Installation)Executes a program periodically, showing output fullscreen.watch -n 1 'date'

Whether you’re a new Linux enthusiast or a seasoned professional, we hope that this guide empowers you with the knowledge and tools needed to navigate and manage your Linux environment with confidence. Keep exploring, experimenting, and learning, as the world of Linux commands is vast and continually evolving. Happy command line adventures!