Linux
Need to use gmail to set up google account with a credit card
What is an Operating System?
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
Time-sharing operating systems schedule tasks for efficient use of the system and may also include accounting software for cost allocation of processor time, mass storage, printing, and other resources.
Linux began in 1991 as a personal project by Finnish student Linus Torvalds: to create a new free operating system kernel. The resulting Linux kernel has been marked by constant growth throughout its history.
The Unix operating system was conceived and implemented by Ken Thompson and Dennis Ritchie (both of AT&T Bell Laboratories) in 1969 and first released in 1970.
Programming language, C, to make it portable.
In 1977, the Berkeley Software Distribution (BSD) was developed by the Computer Systems Research Group (CSRG) from UC Berkeley, based on the 6th edition of Unix from AT&T.
In 1983, Richard Stallman started the GNU project with the goal of creating a free UNIX-like operating system.[7] As part of this work, he wrote the GNU General Public License (GPL). By the early 1990s, there was almost enough available software to create a full operating system.
In 1985, Intel released the 80386, the first x86 microprocessor with a 32-bit instruction set and a memory management unit with paging.[8]D.
The Operating System boots or brings up a kernel
Linux is an operating system that allows users to control computers
Open source -
Denoting software for which the original source code is made freely available and may be redistributed and modified.
Free - (for the most part)
When you login to a Linux system
Access the Cloud Shell
Click on symbol for access to Linux Shell
User name Host name prompt
john_iacovacci1@cloudshell:~ (uconn-engr)$
Ctrl +c will always get prompt back
You can access the system via ssh or putty (on Windows)
these tools allow for terminal emulation (emulate a terminal)
as if it were physically connected to the machine
Google provides access to a Linux Shell by clicking on
>_ icon in the upper right hand part of the screen
All Linux/Unix system have a superuser account called "root"
This account can change passwords, delete files and do everything on the system. Full permissions.
Linux is case sensitive and do not use spaces in file names
A file system is necessary to store files on a computer
The Linux file system starts with the root directory (like a tree)
and branches into subdirectories from the root.
Each sub-directory can have move subdirectories underneath so it is like an upside down tree.
Linux File System Directories
/bin: Where Linux core commands reside like ls, mv.
/boot: Where boot loader and boot files are located.
/dev: Where all physical drives are mounted like USBs DVDs.
/etc: Contains configurations for the installed packages.
/home: Where every user will have a personal folder to put his folders with his name like /home/john_iacovacci1 (taken from my gmail login)
/lib: Where the libraries of the installed packages located since libraries shared among all packages
/root: The home folder for the root user.
/sbin: Like /bin, but binaries here are for root user only.
/tmp: Contains the temporary files.
/usr: Where the utilities and files shared between users on Linux.
/var: Contains system logs and other variable data.
The navigation commands
cd - is change directory
you can change directory to an absolute path e.g.
cd /home/john_iacovacci1
absolute path always begins with /
or relative path to where you currently are set to
cd docs (a directory under /home/john_iacovacci1)
Note: cd $HOME
will take you to your home directory
john_iacovacci1@cloudshell:~ (uconn-engr)$ cd $HOME
john_iacovacci1@cloudshell:~ (uconn-engr)$ pwd
/home/john_iacovacci1
john_iacovacci1@cloudshell:~ (uconn-engr)$
john_iacovacci1@cloudshell:~ (uconn-engr)$ cd docs
john_iacovacci1@cloudshell:~/docs (uconn-engr)$ pwd
/home/john_iacovacci1/docs
john_iacovacci1@cloudshell:~/docs (uconn-engr)$
pwd - stands for print working directory - tells you where you are
ls - lists all files and directories within the working directory (or path you provided)
john_iacovacci1@cloudshell:~/docs (uconn-engr)$ ls
file1
john_iacovacci1@cloudshell:~/docs (uconn-engr)$
linux files have 3 sets of permission attributes
read(r), write(w) and execute(x) for owner, group and everyone
adding the -lt option for (for ownership and time stamp)
The touch command creates a file
$ touch file1
john_iacovacci1@cloudshell:~/docs (uconn-engr)$ ls -lt
total 4
-rw-r--r-- 1 john_iacovacci1 john_iacovacci1 13 Jan 26 21:24 file1
I can now see how the file is permissioned
the chmod command can change the permissions of a file or directory
john_iacovacci1@cloudshell:~/docs (uconn-engr)$ chmod +x file1
john_iacovacci1@cloudshell:~/docs (uconn-engr)$ ls -lt
total 8
-rw-r--r-- 1 john_iacovacci1 john_iacovacci1 13 Jan 26 21:37 file2
-rwxr-xr-x 1 john_iacovacci1 john_iacovacci1 13 Jan 26 21:24 file1
john_iacovacci1@cloudshell:~/docs (uconn-engr)$
to create a directory you use the mkdir command
john_iacovacci1@cloudshell:~ (uconn-engr)$ mkdir images
john_iacovacci1@cloudshell:~ (uconn-engr)$ cd images
john_iacovacci1@cloudshell:~/images (uconn-engr)$
john_iacovacci1@cloudshell:~/docs$ touch file1
to copy a file use the cp command
john_iacovacci1@cloudshell:~/docs$ cp file1 file2
john_iacovacci1@cloudshell:~/docs$ ls -lt
total 20
-rwxr-xr-x 1 john_iacovacci1 rvm 20 Sep 1 22:48 file2
-rw-r--r-- 1 john_iacovacci1 john_iacovacci1 0 Sep 1 22:46 file
-rw-r--r-- 1 john_iacovacci1 rvm 14 Sep 1 22:46 first
-rwxr-xr-x 1 john_iacovacci1 rvm 20 Sep 1 22:46 file1
-rw-r--r-- 1 john_iacovacci1 rvm 12 Jan 28 2020 file4
-rw-r--r-- 1 john_iacovacci1 rvm 12 Jan 27 2020 file3
john_iacovacci1@cloudshell:~/docs$
john_iacovacci1@cloudshell:~/docs (uconn-engr)$ cp file1 file2
john_iacovacci1@cloudshell:~/docs (uconn-engr)$ ls -lt
total 8
-rw-r--r-- 1 john_iacovacci1 john_iacovacci1 13 Jan 26 21:37 file2
-rw-r--r-- 1 john_iacovacci1 john_iacovacci1 13 Jan 26 21:24 file1
john_iacovacci1@cloudshell:~/docs (uconn-engr)$
a wildcard allows you to use any command to pattern match to a file
? - one character
* - all characters
[] - range of characters
ls -lt file?
ls -lt f*
john_iacovacci1@cloudshell:~/docs (uconn-engr)$ ls -lt file?
-rw-r--r-- 1 john_iacovacci1 john_iacovacci1 13 Jan 26 21:37 file2
-rw-r--r-- 1 john_iacovacci1 john_iacovacci1 13 Jan 26 21:24 file1
john_iacovacci1@cloudshell:~/docs (uconn-engr)$
john_iacovacci1@cloudshell:~/docs (uconn-engr)$ ls -lt f*
-rw-r--r-- 1 john_iacovacci1 john_iacovacci1 13 Jan 26 21:37 file2
-rw-r--r-- 1 john_iacovacci1 john_iacovacci1 13 Jan 26 21:24 file1
john_iacovacci1@cloudshell:~/docs (uconn-engr)$
pico is an editor to help create of change files
cat is a command that display contents to a file
john_iacovacci1@cloudshell:~/docs (uconn-engr)$ cat file1
test doc one
john_iacovacci1@cloudshell:~/docs (uconn-engr)$
echo is a command to repeat what you type
john_iacovacci1@cloudshell:~/docs (uconn-engr)$ echo "hello world"
hello world
john_iacovacci1@cloudshell:~/docs (uconn-engr)$
redirection and pipes
redirection allows you to redirect output to a file
john_iacovacci1@cloudshell:~/docs (uconn-engr)$ echo "hello world" > file3
john_iacovacci1@cloudshell:~/docs (uconn-engr)$ cat file3
hello world
john_iacovacci1@cloudshell:~/docs (uconn-engr)$
other file commands are
rm - remove a file
mv - move a file
mkdir - make directory
rmdir - remove directory
pwd — print working directory,
know which directory you are in, absolute path e.g. "/home/username".
ls — Use the "ls" files are in the directory you are in. ls -lt
touch — command is used to create a file.
man --help — how to use command manual pages "man cd”
cp — copy files through the command line.
mv — move files
locate — locate a file in a Linux system
echo — repeats what you type.
cat — display contents of a file.
nano, vi, jed, pico - edit files
sudo — super user do allows you to act as root use.
df — see the available disk space
du — know the disk usage of a file in your system.
tar — work with compressed files
zip, unzip — compress files into a zip and unzip files
chmod — change the permissions granted to it in Linux.
hostname — know your name in your host or network.
“hostname -I” gives you your IP address in your network.
ping — Use ping to check your connection to a server.
clear - clear the terminal
TAB can be used to fill up in terminal.
Ctrl+C can be used to stop any command
exit terminal by using the exit command.
man ls
man - manual for all linux commands
Assignment one - create a directory under your home directory called scripts and create a file called my_profile
1. pwd
should be home/user_name
2. mkdir scripts
3. cd scripts
4. pwd - /home/user_name/scripts
5. Use the terminal editor to access the graphical editor
6. Click into the directory
7. Open a New File - High light the directory you want to create the file in then
right click and select new file.
8. Name the file my_profile
9. Enter the commands into the file
10. Save the file
11. Go back to the Cloud Shell Terminal
12. Change the properties of the file so it can be executable
john_iacovacci1@cloudshell:~/scripts (uconn-engr)$ chmod 755 my_profile
13. Check the file status for executable
john_iacovacci1@cloudshell:~/scripts (uconn-engr)$ ls -lt
total 4
-rwxr-xr-x 1 john_iacovacci1 rvm 136 Sep 1 23:16 my_profile
14. Execute the script
john_iacovacci1@cloudshell:~/scripts (uconn-engr)$ ./my_profile
Hello my name is John Iacovacci
My major is Computer Science
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