Orientation for fresh VDTT students introduce to linux

Prerequisites and Goals• What you should know – Basic familiarity with computers – Working Knowledge of atleast one operating system – A will to learn • What you will know – This is not

Orientation for fresh VDTT Students

Introduction to UNIX

July 28, 2001Anup Gangwar

• Prerequisites and goals of this course

• Differences between UNIX and Windows

• Overview of unices

• Basic UNIX commands and utilities

• Lunch Break

• File editors in UNIX

• Programming and Shell Scripting

• Document formatting using UNIX

• References and further study

• Thank You

Prerequisites and Goals

• What you should know

– Basic familiarity with computers

– Working Knowledge of atleast one operating system

– A will to learn

• What you will know

– This is not a complete UNIX tutorial

– Don’t try to learn the whole UNIX in one day

– How to do the most common set of tasks with UNIX

– Self-Help is the best help

– Pointers for further information

Differences: UNIX and Windows

• The UNIX and Windows philosophies

• Client-Server model of Computation

• Multi-User and Multi-Tasking Login?

• Concept of the Kernel and User Shell

• Concept of file ownership and groups

• GUI on UNIX and X windows

• Tips:

– UNIX is the most used OS in scientific and industrial community

– Instead of avoiding UNIX take it heads on

– Learning UNIX now will help you save precious time later on

Overview of Unices-1

• The ?original? UNIX

• The AT&T SVR and BSD

• Others: HP-UX, Solaris, Linux, AIX, IRIX etc.

• Why are there so many unices? Vendor Wars!

• How do I understand all of them? POSIX!

• Tips:

– Learn the common set of commands for all the unices

– Linux utilities will contain enhancements not found in others

– Try to clear trivial doubts like command syntax yourself

– Processors: Sun Ultra Sparc

– Vendors: Sun Microsystems

– Markets: All ranges of Servers and Workstations

– Markets: Low End Servers and Workstations

• AIX (Advanced UNIX)

– Processors: IBM Power PC

– Vendors: IBM

– Markets: All ranges of Servers and Workstations

Overview of Unices-4

• IRIX

– Processors: MIPS

– Vendors: SGI (Silicon Graphics International)

– Markets: High End Graphics Servers and Workstations

• Others

– BeOS, FreeBSD etc

– RTOS’s: PSoS, QNX, RTEMS, ?RTLinux? etc

What we have

• Philips VLSI Design Lab

– HP Server running HP-UX

Basic UNIX Commands and Utilities-1

• Files and Directories

– File Types: Windows and UNIX

– File and Directory creation (Editors, mkdir, ln etc.)

– Listing contents of a directory (ls)

– File and Directory deletion (rmdir, rm etc.)

– File and Directory permissions (chmod)

– File and Directory ownership (chown, chgrp)

– Organizing your work in directories (mv)

• Tips:

– UNIX doesn’t have a recycle bin!

– Try not to make the mistake of rm -rf * command

Basic UNIX Commands and Utilities-2

• Managing your account

– What is meant by managing your account?

– Concept of setup files

– Why are there so many different Shells?

– Environment variables

– bashrc and cshrc files

– Customizing your environment with bashrc and cshrc files

– Example: The TERM environment variable and stty

– Tips:

• Try an environment variable on command-line first

• Always set the PATH variable properly

Basic UNIX Commands and Utilities-3

• Remote process execution

– Why do we need remote process execution?

– Telnet and rlogin

– Remote execution of graphics programs

• X-Security, granting permissions and colormap

• The DISPLAY environment variable

– dot-rhosts (.rhosts), xon

– Moving files between computers: FTP (?anonymous? FTP login)

– Tips:

• Graphics performance suffers in remote graphics execution

• xhost+ is the worst thing to do!

• Ncftp is a better ftp client than the vanilla default UNIX ftp

Basic UNIX Commands and Utilities-4

• Taking printouts

– Concept of network and local printers

– Printer languages: Postscript and PCL

– GhostView and Acroread programs

– Spooling, Deleting and Checking a printer job

– Duplex printing and mpage

• Taking backups

– Tarring, zipping, gzipping and compressing

– Comparison with winzip and common filename extensions

• Tips:

– Do not issue the command tar -cvf <file-name> *

– Acroread just might be a better program to open pdf files

Basic UNIX Commands and Utilities-5

• Miscellaneous stuff

– Forcing a process in background (&, fg, bg)

– Setting aliases

– Online manual pages, man

– Concept of NIS and NFS

– Changing password, passwd (?yppasswd?)

– Searching for patterns, grep and regular expressions

– Working with files with special characters in names

– The file utility

– finger, who and rwho

– ps and kill

– Mail and mail clients, netscape, pine, emacs and mail

– startx, Xclients and xinitrc files

• Tips:

– Instead of asking someone try man -k

Lunch Break

Editors in UNIX-1

• What all is available, Vi, Emacs, Pico, Joe?, Nedit?

• Vi: The king of all editors? Tutorial?

– Why learn vi?

– Getting in and out?

– Basic keys for editing

• Moving around, deleting, joining lines

• Repeating commands

• Search and replace

– Tips:

• Vim is not Vi

• Learn the keypad scroll key combinations instead of arrow keys

• Vi is fast, try to make the best use of its capabilities

Editors in UNIX-2

• Emacs: Much more than an editor?

– Why learn Emacs? History, Tutorial

– Getting in and out?

– Basic keys for editing

• Moving around, deleting a line

• Search and replace

• Formatted text, postscript spooling

Editors in UNIX-3

• Pico: Is there really a need?

– Pico and Pine

– Editor Keys

• Joe?, Nedit?

– Keys similar to Norton Editor

– Nedit has some features similar to Emacs

• Tips:

– Don’t fall for Pico or Nedit

– Learn Vi and Emacs if you really want to get into UNIX

– In the end it is a matter of choice

Programming on UNIX-1

• Is programming on UNIX tough? What all is available?

• Concept of IDE and differences with TurboC++

• Compilers, Linkers, Debuggers and front-ends

• Managing big projects: make and comparison with TC

project file

• Example of a simple makefile

• GUI development on UNIX

• Java

• Tips:

– UNIX is a programmers paradise

Programming on UNIX-2

• Gcc, The GNU C/C++ compiler

– Simplest possible way to use: gcc <file-name>

• Not every UNIX systems will have gcc

• Turning on optimization makes the compilation slow

Programming on UNIX-3

• Ld, The Linker

– What exactly are libraries?

– Shared and static libraries– Is there a need to call Ld explicitly?

– Passing options to Ld from gcc

• The -l option

• The -L option

• The LD_LIBRARY_PATH environment variable

• The LD_RUN_PATH environment variable

– Tips:

• Always check the Ld on the system, HP-UX doesn’t use GNU Ld

• Environment variables are different with non GNU Ld

Programming on UNIX-4

• Gdb, The GNU C/C++ debugger

– Why is a debugger needed?

– gdb and ?core? File– Common commands

• list

• run, break, resume

• backtrace and where

– Tips:

• Using gdb directly might be tedious

• Try the various front-ends to gdb: emacs, xxgdb, mxgdb etc.

• Not every system will have gdb, you just might have to use ?dbx?

Programming on UNIX-5

• Gmake or GNU make

• What is the need for a Makefile?

– Dependencies– Targets in a makefile– Patterns in makefile– Automatic variables in a makefile– Pattern substitution

– Common target names: all, clean, docs

• Tips:

– Never forget the TAB – Make is language independent!

Programming on UNIX-7

• GUI in UNIX?

– Differences with TurboC++

– Vanilla X windows programming, why not?

• Always provide a command line interface to your programs

• Using a GUI is slow

Programming on UNIX-8

• Java

– What is really different with the windows version?

– Is Jfc, Java2D, Java3D available?

– IDE’s for Java over UNIX?

• Tips:

– Don’t try to use a %.class dependency with make

– If you run Java from a server, graphics would be slow

Introduction to Shell Programming-1

• What is the need for shell programming?

• Bourne shell (sh, ksh, zsh and bash)

• c shell (csh, tcsh)

• Examples of shell programming

– Moving all a.{i}.txt files to a.{i+1}.txt

– Cleaning up your directory at the end of a day

• Tips:

– Perl just might be a better option

– Don’t forget ?sed? and ?awk?

Introduction to Shell Programming-2

• Moving files script

#!/bin/sh -f

FILE_LIST=`ls | grep "\.[0-9]\." `

for CURR_FILE in $FILE_LIST; do

FIRST_NM=`echo $CURR_FILE | cut -d'.' -f1`

NUM=`echo $CURR_FILE | cut -d'.' -f2 `

SECOND_NM=`echo $CURR_FILE | cut -d'.' -f3`

NUM_PLUS=`expr $NUM + 1 `

mv -i $CURR_FILE $FIRST_NM.$NUM_PLUS.$SECOND_NM

done

Introduction to Shell Programming-3

• Cleanup directory script

#!/bin/csh -f

# Assume that ps, pdf etc directories are present

set FILE_LIST=`ls`

foreach CURR_FILE ( $FILE_LIST )

set TST=`echo $CURR_FILE | grep \.pdf\$ ` if( $TST != "" ) then

mv $CURR_FILE pdf endif

set TST=`echo $CURR_FILE | grep \.ps\$ ` if( $TST != "" ) then

mv $CURR_FILE ps endif

end

Text formatting using UNIX-1

• What is the need for text formatting?

• WYSWYG or NOT?

• LaTeX & Emacs PS renderer

• LaTeX WYSWYG front-end Lyx

• Other text formatters: ?troff?

• How to make Presentations? Slides?

• Tips:

– PowerPoint is still the best software for making presentations

– It is easy to convert PowerPoint slides to html

Text formatting using UNIX-2

• LaTeX

– origin: LaTeX and TeX

– usage

– LaTeX tutorials and manuals

• A not so short introduction to LaTeX

• The LaTeX manual

• LaTeX by Lesslie Lamport

• Lyx a WYSWIG interface to LaTeX

• Emacs ps-renderer and troff

• Tips:

– For small formatted text Emacs is still the best

Before wrapping up

Any questions/doubts which you would like to clarify?

Wrapping up

• Self help is the best help!

– The UNIX man pages ?Manual sections?

– Using man, whatis etc

– Experiment You can never kill the system

• Links

– http://www.gnu.org, for GNU tools and manuals

– http://sunsite.unc.edu, world’s largest collection of free software

– http://upavan.cse.iitd.ernet.in, Philips Lab internal page

– http://poorvi.cse.iitd.ernet.in/local, Intel cluster archives

• Books

– The UNIX programming environment, Kernighan & Pike

Thank You