Introduction to UNIX A User’s Perspective: Day 2 – Command Basics.

Introduction to UNIX

A User’s Perspective:Day 2 – Command Basics

Review – UNIX Shells

The basics of UNIX Shells– Types

ksh & bash

– Initialization/configuration scripts /etc/profile & .profile /etc/bash_rc & .bash_rc

Review – File System

Everything is a file Paths Ownership & Permissions

Let’s Log into the Server

A few changes– The server we will use:

137.99.110.55 spf1n5.ucc.uconn.edu

– The login utility: ssh

Why the changes?

Review - Commands

ls – LiSt cd – Change Directory pwd – Present Working

Directory rm – ReMove mkdir – Make Directory mv – MoVe cp – CoPy touch – Create cat – conCATenate echo – Hello…lloo..llooo…

ln – Link chmod – Change permissions chown – Change Ownership

Shortcuts to your home directory

– cd– cd ~– cd ~user-name– cd $HOME

Command Exercise

1. pwd

2. ls -al

3. touch index.html

4. ls –al

5. mkdir –p public_html/test/page

6. cp -p index.html public_html/test/page

7. mv index.html public_html/test

8. cd public_html

9. echo “name Loves UNIX” > test/index.html

10. cd ..

11. echo “Mitch Loves UNIX” > test/page/index.html

12. ln –s test/index.html index.html

13. cat index.html

14. rm test/index.html

15. cat index.html

16. ln test/page/index.html test/index.html

17. cat index.html

18. echo “UNIX rules” >> test/page/index.html

19. cat index.html

What Did We Do?

Some Loose Ends

CTRL-C– Terminate the current process

CTRL-D– Close the connection immediately

What We Will Cover Today

Extend our knowledge and use of commands Learn how to find help Standard I/O/E Redirection & Piping Customize our Shell account Begin to learn VI

Command Arguments

Typically one or more file names the command will operate on

Switches!?! We don’t need no stink’in Switches

Switches give us power/functionality Increase the functionality of a command Almost all commands have available switches Switches are denoted with a – (minus or

hyphen)

Anatomy of a Command

Command-name– Basic function

Command-name arguments– Basic function performed on some file(s)

Command-name –switches– Extended function

Command-name –switches arguments– Extended function performed on some file(s)

Commands - Basic Function

Single function ls, cp, mv, etc.

– Minimal functionality– Minimal output

Commands – Directed Function

Perform the command on a file– What can the file be?

ls index.html rm /u/ux101is1/hdisk0

Commands – Extended Function

Using switch(es) to refine the command output Usually provides more information Always deals with specific function of the base

command

Commands – Directed Extended Function

Refine the operation performed on a file(s) ls –ail index.html

Manual Pages – The UNIX Bible

Everything you need to know… man pages

– System resident manuals

Available: – for most commands– on most UNIX systems– on the Web

http://www.linuxcentral.com/linux/man-pages/

Using man

Syntax– man “command-name”– man –k “descriptor”

Anatomy of a man Page

Purpose Syntax Description Details of switches Examples

Example

cd ~ cd public_html ls –ailF cd test ls –ailF cd .. cp –h index.html .. cd .. ls –al rm index.html

What Should You Know?

Basic Command Use How to use switches and arguments How to find help

Question?

Anyone… anyone?

Redirection & Pipes

Understanding UNIX

Input and Output

What is Input?

Information fed into a data processing system or computer (Merriam-Webster Dictionary)

Data necessary to create some action or output. Text

– ‘Joshua’

Keystroke combinations– CTRL -D

Input Sources

Standard Input (stdin) Device– That part of the operating system controlling from

where a program receives its input.– keyboard

Any defined device capable of receiving input

What is Output?

The information produced by a computer (Merriam-Webster Dictionary)

Data created as a result of some action or input. Text

– ‘Hello Joshua’

Pictures & Graphics–

Output Destinations

Standard Output (stdout) Devices– That part of the operating system that controls where a

program writes its output.– Monitor– Printer

Any defined device capable of receiving output

Redirection

Where? > the redirection operator

– Allows for an output destination other then standard output (stdout).

– Is a write only operation Can only redirect to regular files.

# ls –al /usr > directory.lst

Pipes

Keeping the Flow Going… | the pipe operator

– Allows for the output (stdout) of one command to serve as the input (stdin) of another command

– No write involved in the process Can only be used with commands (executables)

# ls –al /usr/bin | grep ls

Putting it All Together

What do we gain– Extended functionality– Increased control– Innovative solutions– An understanding of both input and output

IN CLASS DEMONSTRATION

SIX Volunteers able to follow instructions– Hmmmm…

A paper | B | C | D | E | F > Frontdesk

A Real World Example

cp –p /u/ux101is1/tfile . ls –al tfile wc tfile sort tfile | wc sort tfile | uniq –c | wc sort tfile | uniq –c | sort –rn > tfile2 wc tfile wc tfile2 more tfile more tfile2

Running Processes

Foreground– Ties up the command-prompt

Loose control

– Not really multi-tasking

Background– Keep control of the command prompt

Maintain control

– Multi-tasking

What’s Running?

ps –ef | grep ux ps aux | more ps –ef | grep “string”

Cron Jobs

Scheduling jobs…– Minute Hour Day Month Day_of_the_Week

Sunday = 0 * = Match all

Examples:– 0,5,10,15,20,25,30,35,40,45,50,55 * * * * $HOME/automation.pl– 0 2 * * 4 /usr/sbin/acct/dodisk– 5 * * * * /usr/sbin/acct/ckpacct– 0 4 * * 1-6 /usr/sbin/acct/runacct 2>/var/adm/acct/nite/accterr

What Should You Know?

– Basic Command Use– How to use switches and arguments– How to find help

Understand Standard I/O/E Understand Redirection Understand Pipes How to use Redirection and Pipes Process management

Question?

Anyone… anyone?

What Will Cover Tomorrow…

Advanced UNIX commands VI

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