Learning unix and C slide

Course grade  Final grade is based on:  Exam  Assignments and final project:  “Black box” tests: automatic tests that run the program and check its output  “White box” tests: code r

Learning Unix and C

Software Project – Winter 2007 / 2008

Administration

The goals of the course

 Learn C

 Learn (a bit) Unix

 Practice software development:

 Understanding software requirements

Course grade

 Final grade is based on:

 Exam

 Assignments and final project:

 “Black box” tests: automatic tests that run the program and check its output

 “White box” tests: code review

Overview (for the rest of this lesson)

 Introduction to Unix

 Development environments for C

 Basic tools in UNIX

 Eclipse

 Visual Studio

 Submission of assignments and project

7Introduction to UNIX

(and Linux…)

 provides programmers and users with an

interface to access those resources.

multi-users, GUI, security, etc.

Thompson & Ritchie at AT&T Bell Labs.

 70’s – Rewritten in C (enables portability).

 80’s – System-V (AT&T) and BSD (Berkeley) versions.

 90’s – Linux by Linus Torvalds.

 For basic introduction and commands

see course web-page ( unix.doc )

Basic commands in Unix shells

Command Short explanation

ls -l prints the content of a directory

pwd prints the name of the current

rm removes (deletes) a file

rmdir removes an empty directory

man help (manual) on a command

Additional Unix commands

 cat – concatenate files and print to standard

output

 cat file1

 cat file1 file2 file3

 less – file viewer (“less” is better than “more”)

 which – locate a command

 groups – prints the groups the user in

(permission )

 grep – prints lines matching to a pattern

 grep –i “.*lib.*” foo.bar

 find – search for a file in a directory

 find –name “*.txt” –print

 find ~/ –name “*.o” -exec rm {} \;

 clear – clears the terminal screen

 finger – prints information about a user

 who – shows who is logged in

 whoami – identifies the current user

File and directory permissions in Unix

 permissions = bits 2-10 (bit 1: “d”=directory, “-” =

file)

 bit 1 = whether is a directory (d) or not (-)

 bits 2-4: owner permissions

 bits 5-7: group permissions

 bits 8-10: other permissions

 rwx:

 r – read permission

 w – write permission

 x – execute (file)/ can cd (directory)

 changing permissions: chmod

 chmod go+rx a.out

 chmod –R 755 mydir

group permissions

Editing text files in Unix

 Common text editors:

 pico - simple but very basic, similar to

Pipes and redirections to/from files

 Pipe: prog1 | prog2 – the output of

prog1 is redirected to the input of prog2

 Example: ls –l | less

 Output redirection to file

 prog > foo.out :may cause an error if foo.out exists

 prog >! foo.out :truncates foo.out if exists

 prog >> foo.out :may cause error if foo.out does NOT exist

 prog >>! foo.out :does not check whether

foo.out exists

 Input redirection (read from file)

 prog < foo.in

Comparing files (program tests)

 prog <1.in >! my1.out : reading from

1.in and writing to 1.out

 diff my1.out 1.out –compares files line

by line

 Ignoring all whitespaces:

diff –w my1.out 1.out

Development environments for C

C programming process

Hello.c Edit Compile Hello.o Link Hello

Executable Output

19Basic tools in UNIX

Compiling and linking

 Compiling and linking

 gcc hello.c –o hello

 Only compiling (creating hello.o)

 gcc –c hello.c

 Only linking

 gcc hello.o –o hello

 Additional common flags to gcc:

 -g – allows debugging

 -l<library-name> - linking with external

libraries

Make and makefiles (in short)

 makefile: a collection of rules to make targets

 make: a utility that “executes” makefiles

-rm hello.o hello hello: hello.o

gcc -g hello.o -o hello hello.o: hello.c

gcc -c -g hello.c

rule

target name dependencies

command

gdb – the GNU debugger

 Running gdb: gdb <exe>

 Useful commands: help, quit, n, s,

b <function>/<#line>

23Eclipse

(Linux)

 Including C/C++ projects

 Code requires porting to LINUX

 Relatively complicated installation

Create a new workspace

/a/home/cc/students/cs/ozery/soft-proj08

Create a new project-1 (Linux lab)

Create a new project -2 (Linux Lab)

create a new project (windows)

Add source file

Add makefile (a file named “makefile”)

Project properties (windows)

Build the project

Running and Debugging (LINUX lab)

 Right click on the executable file (with the bug icon ):

 Run As->Local C/C++ Application

 Debug As->Local C/C++ Application

 Set debugger to “GDB Debugger”

Debugging under Windows+cygwin

Console in a new window

Microsoft Visual Studio

Advantages / disadvantage, download info

 Advantages:

 A common and friendly IDE for C/C++.

 Recommended for development under Windows

 A relatively simple installation, good support in the internet

 Disadvantage: requires porting to Linux

 Downloads:

 Visual Studio Express C++ (2005 edition)

(see http://msdn2.microsoft.com/visualc/)

 Free download (2003 edition) at CS School

“burning station” (see FAQ)

 Available in the CS School Linux Lab – via

nt-nlb application Requires Windows account.

Creating a project (and a solution)

Adding new source files

 Right click on project name: Add->New Item

Write file name, including the c suffix (e.g file.c)

Build project

Compiling with debug information

Removing optimization

Linking with debug information

Debugging

45Submission of assignments

and project

 The submitted directories of the two

partners should be identical!

 Perform rebuild: make clean + make all

 Verify correct run: use given input/outfile + diff.

Output should be exactly as specified! (do not add unnecessary friendly “printf” commands!)

 Before submission – give permission

 submitted to the checker’s mail-box (details

will be given later)

Grading policy

 If you do not follow the submission

guidelines and your exercise cannot

 a detailed description of your appeal

 the original printout (with the checker’s comments).