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Useful Commands!
These are useful Linux commands to know for the BASH shell.
System information
| Command | Description |
|---|---|
| uname -a | Displays all system information |
| hostnamectl | Shows current hostname and related details |
| lscpu | Lists CPU architecture information |
| timedatectl status | Shows system time |
System monitoring and management
| Command | Description |
|---|---|
| top | Displays real-time system processes |
| htop | An interactive process viewer (needs installation) |
| df -h | Shows disk usage in a human-readable format |
| free -m | Displays free and used memory in MB |
| kill | Terminates a process |
Running commands
| Command | Description |
|---|---|
| [command] & | Runs command in the background |
| jobs | Displays background commands |
| fg | Brings command to the foreground |
Service management
| Command | Description |
|---|---|
| sudo systemctl start | Starts a service |
| sudo systemctl stop | Stops a service |
| sudo systemctl status | Checks the status of a service |
| sudo systemctl reload | Reloads a service’s configuration without interrupting its operation |
| journalctl -f | Follows the journal, showing new log messages in real time |
| journalctl -u | Displays logs for a specific systemd unit |
Cron jobs and scheduling
| Command | Description |
|---|---|
| crontab -e | Edits cron jobs for the current user |
| crontab -l | Lists cron jobs for the current user |
File management
| Command | Description |
|---|---|
| ls | Lists files and directories |
| touch | Creates an empty file or updates the last accessed date |
| cp | Copies files from source to destination |
| mv | Moves files or renames them |
| rm | Deletes a file |
Directory navigation
| Command | Description |
|---|---|
| pwd | Displays the current directory path |
| cd | Changes the current directory |
| mkdir | Creates a new directory |
File permissions and ownership
| Command | Description |
|---|---|
| chmod [who][+/-][permissions] | Changes file permissions |
| chmod u+x | Makes a file executable by its owner |
| chown [user]:[group] | Changes file owner and group |
Searching and finding
| Command | Description |
|---|---|
| find [directory] -name | Finds files and directories |
| grep | Searches for a pattern in files |
Archiving and compression
| Command | Description |
|---|---|
| tar -czvf [files] | Compresses files into a tar.gz archive |
| tar -xvf [destination] | Extracts a compressed tar archive |
Text editing and processing
| Command | Description |
|---|---|
| nano | Opens a file in the Nano text editor |
| cat | Displays the contents of a file |
| less | Displays the paginated content of a file |
| head | Shows the first few lines of a file |
| tail | Shows the last few lines of a file |
| awk ‘{print}’ | Prints every line in a file |
User management
| Command | Description |
|---|---|
| w | Shows which users are logged in |
| who | Shows which users are logged in |
| sudo adduser | Creates a new user |
| sudo deluser | Deletes a user |
| sudo passwd | Sets or changes the password for a user |
| su | Switches user |
| sudo passwd -l | Locks a user account |
| sudo passwd -u | Unlocks a user password |
| sudo chage | Sets user password expiration date |
Group management
| Command | Description |
|---|---|
| id [username] | Displays user and group IDs |
| groups [username] | Shows the groups a user belongs to |
| sudo addgroup | Creates a new group |
| sudo delgroup | Deletes a group |
These are useful POWERSHELL commands to know.
| Command | Description |
|---|---|
| Soon | Soon |
These are useful DOCKER commands to know.
| Command | Description |
|---|---|
| sudo docker exec -u 0 -it [Docker ID/NAME] bash | This is the get a bash shell from the container |