COSC102 Notes

Terminal VS. Shell

The terminal is an application/program that can be used to issue commands to the computer. Runs a shell.

The shell is the layer that transfers the command from the keyboard to the actual OS.

Linux and Unix

The kernel is the core part of a computer that manages hardware. An operating system is software that manages hardware and software and provides user services. Unix is a complete multiuser OS, and Linux is a Unix-like kernel that becomes a full OS when combined with tools and applications.

• An operating system (OS) is software that manages a computer’s hardware and software resources, provides common services for programs, and allows users to interact with the computer.

Terminal commands and uses:

Command	Use	Example	Additional Notes
ls	List files in the current directory. For more detailed listing of the directory contents, type " -l" after "ls."		-a -- see hidden files -l -- more information
cd	Moves to a different directory. Type "cd .." to go back one directory.
pwd	Verifies your current directory.
mkdir	Makes a directory
rm	Removes a file or directory. To remove a directory, add "-r" before the folder name. Does not give warnings.
rmdir	Removes a directory only if it's empty.
mv	Moves a file or a directory or renames them
ssh	Connects to other machines	ssh username@hydra0.eecs.utk.edu
nano	Text Editor
vi/vim	Another text editor. To exit, press esc then type ":q"(exits without saving). Press enter after.		vim is a terminal-based text editor Three main modes: Normal (cannot type text/command mode), insert mode (where you actually type text), and command-line mode (save, quit, searching) How to enter/exit insert mode: i -- insert at cursor; a -- insert after cursor; o -- open new line below; O -- open new line above To exit insert mode press esc. Command line mode: :w --> save; :q --> quit; :wq --> save and quit; :q! --> quit without saving
g++	C++ Compiler. Makes an executable from C++ course code files.		simple g++ source.cpp g++ -o exec_name source(s) g++ -std=c++11 -o exec source(s)
clear	Clears the screen.	clear
cp	Copies a file. Input the name of file you want to copy after cp, if you want to specify the destination of the new file, input it after.		scp -- copy variant, for transfer from one machine to another -- scp ~ username@hydra12.eecs.utk.edu:path
man	Short for "manual." Quick and easy way to access useful documentation on any command. Type it before any command.
w	Shows who is logged on and what they are doing.	w
who	Shows who is logged on and where they are	who
chmod	Changes file or directory permissions	chmod 755 test.cpp	user, group, world IMPORTANT(TEST): r=read=4, w=write=2, x=execute=1 Number beside chmod is sum. (ex.) 7 -- can read, write, and execute; 5 -- can read and execute Default = 700 (ex.)chmod 755 -- user:7; group:5; world:5 0: nothing
lscpu	Shows detailed information about your CPU in a clean, human-readable format
lshw	Shows detailed information on system's hardware.
hostname -i	Prints IP address(es) associated with your machine's hostname	hostname -i

• * -- all files
• . -- into current directory