Linux Workshop

This introduction will be a brief intro on how to use Linux. Linux is an operating system that powers many devices that range from webservers to cell phones.

File Structure

In Linux the file system is structred as shown

/: Root of the file system

/etc: Contains system wide configurations

/usr: Contains system installed files such as programs like vim

/var: Contains variable data such as logs

/home: Contains user directories

Navigating the file system

Knowing how to navigate around the Linux filesystem is a basic but critical skill.

The following are a couple of critical commands for navigating around.

• ls
• cd
• pwd

ls

This command will allow you to list all files and directories in your current working directory

cd

This command will allow you to change your directory

pwd

This command will return what your current working directory is

Processes

• ps
• top
• kill

ps

This will list processes that are running Running ps -u $user will allow you to see what process belong to a certain user

top

This will list the process tree for the entire OS

kill

Does exactly as the name implies and kills a process

kill $(pidof $process_name) will kill an instance of $process_name.

Getting system info

• ifconfig
• lspci
• lscpu
• lsmod
• uname
• w
• cat /etc/*releases

ifconfig

Displays and allows control of network interfaces

lspci

This will list pci devices

lscpu

This will list cpu info

lsmod

This will list kernel modules

uname

This will list a variety of system info ie kernel version

w

This will list who is logged in

cat /etc/*releases

Specific distribution will be displayed

Viewing, creating, and editing files

• vim
• less
• cat
• tail
• rm
• mkdir
• touch

vim

Text editor

less

Lets you read through text with vim controls

cat

Allows you to concactenate and print files

tail

Lets you see the newest lines appened to a file tail -f allows you to follow a file in real time

rm

Removes files rm -rf will recursively force remove which while useful can also accidently destroy alot of work. Use with care

mkdir

Lets you create directories

touch

Allows you to either create a new file or change an existing files timestamp

SSH

• ssh user@hostname

Useful tools

• grep
• tmux
• awk
• sed
• ping
• netstat
• scp

grep

Lets you search through files or strings piped into it ls | grep -i myhw will search the output of ls and try to find 'myhw'

tmux

Allows you to split your terminal into multiple sessions from a single session

awk

Lets you sort and print strings awk '{print $1}' FILE Will print the first coloumn from a file

sed

Lets you edit strings sed -i s/stringtoreplace/stringreplacewith/g

ping

Allows you to ping other devices

netstat

Gives you info on network interfaces and very useful in seeing what ports are open

scp

Lets you transfer files

Man pages

If you don't know the arguments or how to use a command just read the man pages

Example

man ls will display the arguments and some info on the ls command