[LINUX] A comprehensive list of commonly used Linux commands, grouped by category:

1. File and Directory Operations

• ls: List directory contents
• lsof: List open files
• cd: Change the current directory
• pwd: Print the current working directory
• cp: Copy files and directories
• mv: Move/rename files and directories
• rm: Remove files or directories
• mkdir: Create directories
• rmdir: Remove empty directories
• touch: Create empty files or update timestamps
• cat: Concatenate and display files
• more: View file contents one screen at a time
• less: View file contents with backward movement
• head: Output the first part of files
• tail: Output the last part of files
• find: Search for files in a directory hierarchy
• locate: Find files by name
• nice: Run a command with modified scheduling priority
• renice: Alter priority of running processes
• ulimit: Get and set user limits

2. File Permissions

• chmod: Change file modes or Access Control Lists
• chown: Change file owner and group
• chgrp: Change group ownership

3. Text Processing

• grep: Print lines matching a pattern
• sed: Stream editor for filtering and transforming text
• awk: Pattern scanning and processing language
• cut: Remove sections from each line of files
• sort: Sort lines of text files
• uniq: Report or omit repeated lines
• tr: Translate or delete characters
• wc: Print newline, word, and byte counts for each file
• diff: Compare files line by line
• patch: Apply a patch to a file
• xxd: Make a hexdump or do the reverse
• iconv: Convert text from one character encoding to another
• split: Split a file into pieces
• paste: Merge lines of files

4. Compression and Archiving

• tar: Store and extract files from an archive file
• gzip: Compress files
• gunzip: Decompress files
• zip: Package and compress files
• unzip: Extract compressed files from a ZIP archive

5. Networking

• ping: Send ICMP ECHO_REQUEST to network hosts
• ifconfig: Configure a network interface
• ip: Show/manipulate routing, devices, policy routing, and tunnels
• netstat: Print network connections, routing tables, interface statistics
• ss: Another utility to investigate sockets
• scp: Secure copy (remote file copy program)
• ssh: OpenSSH SSH client (remote login program)
• ftp: Internet file transfer program
• wget: Non-interactive network downloader
• curl: Transfer data from or to a server
• nmap: Network exploration tool and security/port scanner
• traceroute: Print the route packets take to the network host
• dig: DNS lookup
• telnet: User interface to the TELNET protocol
• resync: Remote file and directory synchronization

6. System Monitoring and Performance

• top: Display Linux tasks
• htop: Interactive process viewer
• ps: Report a snapshot of current processes
• df: Report file system disk space usage
• du: Estimate file space usage
• free: Display amount of free and used memory in the system
• uptime: Tell how long the system has been running
• iostat: Report CPU and input/output statistics
• vmstat: Report virtual memory statistics
• dmesg: Print or control the kernel ring buffer
• hostname: Show or set the system’s hostname

7. Disk Management

• fdisk: Partition table manipulator for Linux
• mkfs: Build a Linux file system
• mount: Mount a file system
• umount: Unmount file systems
• fsck: File system consistency check and repair

8. User Management

• useradd: Create a new user or update default new user information
• usermod: Modify a user account
• userdel: Delete a user account and related files
• passwd: Update user's authentication tokens (password)
• groupadd: Create a new group
• groupmod: Modify a group
• groupdel: Delete a group
• su: Substitute user identity
• sudo: Execute a command as another user
• id: Print user and group information
• unmask: Set default file permissions.

9. System Management

• systemctl: Examine and control the systemd system and service manager
• service: Run a System V init script
• shutdown: Halt, power-off, or reboot the machine
• reboot: Reboot the system
• halt: Halt the system
• cron: Daemon to execute scheduled commands (crontab)
• at: Schedule commands to be executed at a later time
• kill: Send a signal to a process
• killall: Kill processes by name
• pkill: Look up or signal processes based on name and other attributes
• bg: Resume a job in the background
• fg: Bring a job to the foreground
• jobs: List active jobs

10. Package Management (Debian based)

• apt-get: APT package handling utility
• apt-cache: Query the APT cache
• dpkg: Debian package manager
• apt: High-level interface for the package management system

11. Package Management (Red Hat based)

• yum: Package manager for RPM based distributions
• dnf: Next-generation package manager for RPM based distributions
• rpm: RPM package manager

12. Miscellaneous

• alias: Define or display aliases
• unalias: Remove alias definitions
• echo: Display a line of text
• date: Display or set the date and time
• cal: Display a calendar
• history: Command history
• uname: Print system information
• whoami: Print effective user ID
• man: An interface to the system reference manuals
• info: Read Info documents
• clear: Clear the terminal screen