1.1. Linux Commands and Vim #

Common Commands #

Command	Description	Example
cd	Changes the current directory	`cd dir1`
cat	Outputs the contents of the file	`cat file.txt`
echo	Outputs the specified argument (to stdout)	`echo Hello`
ls	Lists files in the specified directory	`ls dir1`
rm	Removes (deletes) a file or directory	`rm file.txt`
man	Shows the manual page for the specified command	`man ping`
exit	Exits the current terminal session	`exit`
mkdir	Creates a new directory	`mkdir dir2`
which	Shows the full path of a command in the $PATH	`which google-chrome`
pwd	Prints the current working directory	`pwd`
tree	Outputs a list of files and directories in tree form	`tree dir1`
ln	Creates a new link	`ln dir1 linktodir`
find	Helps find data in file hierarchies (can be used for many advanced things)	`find ./ -name "*.txt"`
ps	Lists processes running on the system	`ps -ef`
grep	Searches a string for matches (basically a Find function)	`grep tofind file.txt`
tail	Outputs the last lines of a file	`tail log.txt`
head	Outputs the first lines of a file	`head file.txt`
touch	Updates the access times for a file, or can just be used to create a blank file	`touch file.txt`
mv	Moves or renames a file or directory	`mv file.txt newname.txt`
diff	Shows the differences between two files	`diff file-v1.txt file-v2.txt`
whoami	Outputs your current username	`whoami`

Note: folders should be called directories in Linux/Unix.

Vim is a highly-configurable text editor for Linux and Unix.

Command: vi or vim

Vim operates in 2 modes: Command and Insert
- Command mode allows you to use your keyboard to enter commands
- Insert mode allows you to enter text and edit a file
By default Vim opens in Command mode
- You can change to Insert mode by hitting i (there are more keys to do this)
- You can go back to Command mode by hitting esc
No one appears to know how to exit Vim
- :wq: Save (write) and quit
- :q!: Quit without saving

Cursor Movement
- h j k l: up, down, up, right
- Most versions allow arrow keys
Delete
- dd: Delete line
- x: Delete at cursor
- dw: Delete word
- r: Replace a character
- D: Delete to end of line
Editing
- yy: Copy (yank) a line
- nyy: Copy n lines
- p: Paste above current line
- P: Paste below current line
- ?string: Search backwards for string
- /string: Search forwards for string
- .: Repeat last command
- u: Undo last command