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"