A place to just document useful commands and all the good stuff in the terminal I’ve found useful so far.
Basic Commands
| Command | Description |
|---|---|
| ls | List contents (short) |
| ls -l | List contents (long) |
| ls -a | List contents w/ hidden files |
| ls -lh | Long Listing with human readable file sizes |
| ls -R | List contents recursively |
| cd | Home directory |
| cd {directory} | Change directory |
| sudo {command} | Runs command as super user |
| sudo !! | Runs sudo on previous command |
| top | Displays all active processes |
| clear | Clear screen |
| reset | Reset screen |
| q | Quit |
Shortcuts
| Command | Description |
|---|---|
| Tab | Autocomplete |
| Ctrl + C | Kill Process |
| Ctrl + D | Exit Shell |
| Ctrl + L | Clear Screen |
| Ctrl + Z | Puts whatever you are running into a suspended background process. fg restores it. |
| Ctrl + A | Go to beginning of current line |
| Ctrl + E | Go to end of current line |
| Ctrl + U | Clears line before cursor position |
| Ctrl + K | Clears line after cursor position |
| Ctrl + W | Deletes word before cursor |
File System Management
| Command | Description |
|---|---|
| pwd | List current working directory |
| touch {file} | Create file |
| cat {file} | Concatenate file and display on command line |
| rm {file} | Remove file (permanent) |
| rm -rf {directory} | Delete folder and its contents (Recursively force remove) |
| mv {file} {newFile} | Move/Rename file |
| cp {file} {newFile} | Copy to file |
| touch {file} {directory} | Copy to folder |
| grep {pattern} {file} | Searches file(s) for specific pattern |
| mkdir {directory} | Create directory |
| rmdir {directory} | Delete directory |
Pipe
Piping is essentially chaining the outputs of a command into the input of the following command.
| Command | Description |
|---|---|
| {command} | {command} | Push output of command 1 into command 2 |
| {command} > {file} | Push output to a file (overwrite) |
| {command} >> {file} | Push output to a file (append) |
Example: Grab all instances of foo from command line history
history | grep foo | less
Example: Pipe output in to grep
man curl | grep verbose
Flags
Flags are command line parameters appended to a command to specify certain settings, multiple flags can be used in combination. **Note -** The following examples will be based on the command “`ls“`. Flags will vary depending on the command they are affiliated with. The following examples are just “common” flags that you may or may not see in other commands.
| Command | Description |
|---|---|
| -a | All (including files starting with .) |
| -A | Almost all (not including files starting with .) |
| -d | List directory entries instead of contents |
| -f | Do not sort |
| -h | Human readable |
| -I {Pattern} | Do not show entries with {Pattern} |
| -r | Reverse order |
| -R | Recursive |
| -s | Print size |
| -S | Sort by size |
| man {command} | Look up list of flags |
Example: Grab all files at a specific location with a specific pattern
grep -l -f /src/bin/foo bar
History
| Command | Description |
|---|---|
| history n | Display previous commands inputed (limit to n) |
| Ctrl + R | Search through command history |
| jobs | List all the current jobs |
| !! | Execute previous command |
Job Control
Job control allows you to have multiple processes or “jobs”, essentially run by the shell. Press ctrl + z when in a program (ex – vim) to back out of it and put it into the background.
| Command | Description |
|---|---|
| Ctrl + Z | Back out of program and put into background |
| jobs | List all the current jobs |
| bg/fg {job} | Move job to the background or foreground |
| kill {job} | Kill a specific job |
Example: Send job “top” to foreground
[1]+ Stopped top brandon@brandon-Inspiron-560:~$ fg "%top"
Networking
“`telnet“` and “`netcat“` are both networking commands for reading from and writing to network connections using TCP or UDP. “`wget“` and “`curl“` are programs that retrieve content from web servers.
| Command | Description |
|---|---|
| telnet {application} | Command line interface client to TCP application |
| netcat {application} | Better (arguably) command line interface client to TCP application |
| netstat | Lists all the TCP/UDP connections on your network |
| curl {URL} | Retrieve URL page |
| wget {URL} | Retrieve URL page |
Examples coming soon!!!
Help and Documentation
| Command | Description |
|---|---|
| {command} --help | Display help |
| man {command} | Display command's documentation |
| whatis {command} | Display one line description |
Other Useful Stuff
| Command | Description |
|---|---|
| >> (Heredocs) | Execute all commands within these lines between the two points. |
| chmod +x {script} | Make your bash script an executable |
Example: Send a GET request to a local host
$ nc localhost 8008 << HERE > > GET /api/v0/course/all HTTP/1.0 > > HERE
Linux Safe Reset
Alt + SysRq + R E I S U B "Reboot even if system utterly broken"