Linux Workflow Familiarization

Linux User Group, Thapar University

29 February 2016

LINUX

Work Free. Play Free. Live Free.

Linux Basics

A few things you should know about it

File System

Linux has a single root filesystem
It follows the Filesystem Hierarchy Standard

What is the terminal?

A terminal or a command prompt is a character based interface to the OS.

All it does, literally, is execute the program you tell it to.

Access Control

Some commands require superuser (admin) priviledges.

For that we use sudo.

xkcd.com

Working with Terminals

A few things about Linux terminals

Many types

Different Linux distros have different desktop environments and different terminal shells

E.G. - bash, ksh, zsh, tcsh

Autocompletion

Most terminal shells support automatic completion of commands, options and filenames.

This is activated by single or double press of <Tab> key.

Redirection

The pipe operator '|' is used to redirect the output of one command to the next (left-to-right).

Redirection operators < and > can be used to read from or write to a file.

Operators << and >> are used to read from or append to a file.

Navigation

Commands to help you find your way

Where am I?

$ pwd
/home/seeker

The 'pwd' command tells your location in the filesystem

What is in this folder?

The 'ls' command lists the files and folders in the present working directory

How do I change folder?

The 'cd' command lets you change your location

$ pwd
/home/seeker
$ cd Documents/
$ pwd
/home/seeker/Documents
$ cd ..
$ pwd
/home/seeker

Working with files

Commands to help you do basic operations with files

View Files

In order to print file to terminal, we use 'cat'.

To scroll through big files, use 'less'.

To exit the program, press q.

Move or Copy Files

In order to move a file we use 'mv'. It can also be used to rename the file.

'cp' is used to copy a file.

$ mv soup.py Documents/wolololo.py

$ cp soup.py Documents/wolololo.py

Create Directory

'mkdir' creates a folder.

$ mkdir Documents/test

Delete Files

'rm' can delete a file.

'rmdir' can delete an empty directory.

$ rm soup.py

$ rmdir test

'rm -r' deletes the directory and everything in it.

$ rm -r test

Edit Text- based files

In order to edit a file in terminal we can use 'vi' editor

A simpler and lightweight alternative is 'nano'

Advanced File description

'diff' is used to compare two files for differences.

'file' is used to ascertain type of file.

Generic Commands

Commands that can come very handy

Manual Pages

'man' opens documentation on usage of programs.

'man -k' searches for all available commands.

parameter '--help' shows basic usage information.

Strings

'grep' is a powerful string searching utility.

'wc' is used to generate statistics about strings.

'nl' is used to number lines.

File search

'find' is used to search for files in real time.

'locate' is used to search for indexed files.

Revision

Redirection: pipe operator '|', <, >, <<, >>

Current location: pwd

List files: ls , tree

Change directory: cd

Open text based file: cat, less

Revision

Edit text based file: nano, vi/vim

Usage help: man, --help, info

String searching: grep, strings

File searching: locate, find

Root privilege access: sudo

Process Management

Commands to handle processes

Check Active Processes

'ps' is used to list the processes attached to that shell.

'ps -A' is used to list all processes running on the machine.

Kill Processes

'kill' is used to terminate a background process.

ctrl+c is used to terminate the foreground process.

Background Processes

ctrl+z is used to suspend a process.

Appending & executes a command as a background process.

'jobs', 'bg' and 'fg' can help manage background processes.

OS based commands

Commands to interact with the linux environment

Users and User Groups

Linux's way of managing permissions etc.

File permissions

A file in linux has three kinds of permissions associated with it: read, write and execute.

$ chmod 764 scraper.sh

The command 'chmod' allows us to edit the permissions of a file, also called modes.

	Owner	Group	Other
Read	Y	Y	Y
Write	Y	Y	N
Execute	Y	N	N
Numeric:	7	6	4

$ chmod 764 scraper.sh
$ chmod +ux scraper.sh

Installing Software

Linux distros come with package managers.

Software for linux often need to be processed using 'make' to install it.

E.G.- apt-get (dpkg), pacman, yum

Revision

List processes: ps

Terminate processes: kill, kill -2, kill -9

Manage background jobs: jobs, bg, fg

Run as background process: &

Edit file permissions: chmod +-augorwx

Revision

Keyboard Shortcuts:

Ctrl-C	Terminate foreground process safely
Ctrl-Z	Suspend foreground process
Ctrl-D	Close current shell
Ctrl-L	Clear shell buffer

How to learn about Linux?

The best way to learn about linux is to explore, use creativity to create hacks for whatever you wanna do (hacks are the norm in linux) and to google (or duckduckgo) for whatever you want to do.

Where to start?

This free Introductory course by Linux Foundation on edx.org can get you started. FYI, the course is much more detailed than these slides.

Thank You

Can you now tell me what does do?

$ ./a.out

/LinuxUsrGrp.ThaparUniversity

slid.es/shubham_/linux_workshop

/LinuxUserGroup.tiet

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