🗂️ File & Directory Management
| Command | Description |
|---|---|
| ls | List directory contents |
| cd | Change directory |
| pwd | Print working directory |
| mkdir | Create new directory |
| rmdir | Remove empty directory |
| touch | Create empty file |
| cp | Copy files/directories |
| mv | Move or rename files/directories |
| rm | Remove files/directories |
| find | Search for files/directories |
| locate | Find files using database |
| tree | Display directory structure |
| stat | Show file/directory status |
| file | Identify file type |
| basename | Extract filename from path |
| dirname | Extract directory path |
| du | Disk usage of files/directories |
| df | Disk space usage |
| lsblk | List block devices |
| mount | Mount filesystem |
🔐 Permissions & Ownership
| Command | Description |
|---|---|
| chmod | Change file permissions |
| chown | Change file owner/group |
| chgrp | Change group ownership |
| umask | Set default permissions |
| getfacl | Get file ACL |
| setfacl | Set file ACL |
| id | Show user/group IDs |
| whoami | Current user |
| groups | Show user’s groups |
| sudo | Run command as another user |
🧠 Process & Job Control
| Command | Description |
|---|---|
| ps | List running processes |
| top | Real-time process monitor |
| htop | Enhanced top (if installed) |
| kill | Terminate process by PID |
| pkill | Kill process by name |
| nice | Start process with priority |
| renice | Change process priority |
| jobs | List background jobs |
| fg | Bring job to foreground |
| bg | Resume job in background |
📡 Networking
| Command | Description |
|---|---|
| ip | Show/manipulate IP settings |
| ifconfig | Legacy IP configuration |
| ping | Test network connectivity |
| traceroute | Trace route to host |
| netstat | Show network connections |
| ss | Show socket statistics |
| curl | Transfer data from/to server |
| wget | Download files from web |
| host | DNS lookup |
| dig | DNS query tool |
📦 Package Management (Debian-based)
| Command | Description |
|---|---|
| apt | Package manager |
| apt-get | Install/remove packages |
| dpkg | Debian package tool |
| apt-cache | Query package info |
| snap | Manage snap packages |
📦 Package Management (RHEL-based)
| Command | Description |
|---|---|
| yum | Package manager (older) |
| dnf | Package manager (newer) |
| rpm | Red Hat package tool |
| repoquery | Query package repositories |
| subscription-manager | Manage RHEL subscriptions |
🧮 Text Processing
| Command | Description |
|---|---|
| cat | View file contents |
| less | View file page-by-page |
| more | View file page-by-page |
| head | Show first lines |
| tail | Show last lines |
| grep | Search text |
| awk | Pattern scanning/processing |
| sed | Stream editor |
| cut | Remove sections from lines |
| sort | Sort lines |
| uniq | Remove duplicate lines |
| wc | Word/line/char count |
| tr | Translate/delete characters |
| tee | Redirect output to file + stdout |
| xargs | Build command from input |
🧰 System Info & Monitoring
| Command | Description |
|---|---|
| uname | System info |
| hostname | Show/set hostname |
| uptime | System uptime |
| free | Memory usage |
| vmstat | System performance |
| iostat | CPU/disk I/O stats |
| lscpu | CPU architecture info |
| lsusb | USB devices |
| lspci | PCI devices |
| dmesg | Kernel messages |
👥 User & Group Management
| Command | Description |
|---|---|
| useradd | Add new user |
| usermod | Modify user |
| userdel | Delete user |
| passwd | Change password |
| groupadd | Add new group |
| groupmod | Modify group |
| groupdel | Delete group |
| su | Switch user |
| who | Who is logged in |
| last | Show login history |
🧱 Archiving & Compression
| Command | Description |
|---|---|
| tar | Archive files |
| zip | Compress files |
| unzip | Extract zip files |
| gzip | Compress files |
| gunzip | Decompress gzip files |