Lab46 Wiki

An assembler is a program used for converting instructions written in low-level code into machine level code.

Demonstration of the chosen keyword.

lab46:~$ touch file.asm
lab46:~$ nasm -f bin file.asm -o file.o
lab46:~$ ls
file.asm
file.o
lab46:~$ 

A linker is a program used with a compiler or assembler to provide links to the libraries needed for an executable program.

Demonstration of the chosen keyword.

lab46:~$ ld -o fileA hello.o
lab46:~$ ls
lab46:~$
fileA
hello.o

A piece of software that processes text, for example to remove unwanted spaces or to format it for use in another application.

Demonstration of the chosen keyword.

lab46:~$ touch apple.txt
lab46:~$ vi apple.txt
core 
worm seed
jewel
lab46:~$ cat apple.txt

core 
worm seed
jewel

lab46:~$ cat apple.txt | sed -e "s/e/WWW/"
corWWW
worm sWWWed
jWWWwel

lab46:~$ cat apple.txt | sed -e "s/e/J/g"
corJ
worm sJJd
jJwJl

A source code is a text listing of commands to be compiled or assembled into an executable computer program.

Demonstration of the chosen keyword.

lab46:~$ cat helloC.c
/*
 * helloC.c - a simple "Hello, World!" in C.
 *
 * To compile: gcc -o helloC helloC.c
 */

// include standard I/O functions
//
#include <stdio.h>

// main() function
//
int main()
{
 puts("Hello, World!\n");
 return(0);
}

lab46:~$

Act of checking some sequence of tokens for the presence of the constituents of some pattern

. Match any character

* Match 0 or more of the preceding

^ Beginning of line or string

$ End of line or string

[ ] Character class - match any of the enclosed characters

[^ ] Negated character class - do not match any of the enclosed characters

\< Beginning of word

\> End of word

lab46:~$ grep ^[b-d][aeiou] /etc/passwd
daemon:x:1:1:daemon:/usr/sbin:/bin/sh
bin:x:2:2:bin:/bin:/bin/sh
backup:x:34:34:backup:/var/backups:/bin/sh
lab46:~$

Procedures followed or measures taken to ensure safety

lab46:~$ id tedmist1 (username)
uid=5763(tedmist1) gid=5000(lab46) groups=1730(unix),5763(tedmist1),5000(lab46)

A library is a collection of subroutines or classes used to develop software.

ar(1) - Maintain portable archive or library.

lab46:~$ ar cq lib.a *.o
lab46:~$ ls
lib.a

ar [arguments] [ posname ] archive file. - Arguments can be found in the man pages of ar. Use man ar.

Some arguments include:

- c: create a new library

- q: add the named file to the end of the archive

- r: replace a named archive/library member

- t: print a table of archive contents

Regular expressions, also referred to as regex or regexp, are search criteria for text pattern matching that provide more flexibility than simple wild-card characters.

These Regular Expressions are as follows:

1. . Match any character
2. * Match 0 or more of the preceding
3. ^ Beginning of line or string
4. $ End of line or string
5. [ ] Character class - match any of the enclosed characters
6. [^ ] Negated character class - do not match any of the enclosed characters
7. \< Beginning of word
8. \> End of word

lab46:~$ grep ^[b-d][aeiou] /etc/passwd
daemon:x:1:1:daemon:/usr/sbin:/bin/sh
bin:x:2:2:bin:/bin:/bin/sh
backup:x:34:34:backup:/var/backups:/bin/sh
lab46:~$

Pattern matching is making use of a pattern, usually a regular expression, and trying the pattern various ways on a string to see whether there's any way to make it fit.

The method of measurement will be the understand and how to successfully incorporate pattern matching expressions, such as the ones below.

Follow your method and obtain a measurement. Document the results here. . Match any character

* Match 0 or more of the preceding

^ Beginning of line or string

$ End of line or string

[ ] Character class - match any of the enclosed characters

[^ ] Negated character class - do not match any of the enclosed characters

\< Beginning of word

\> End of word

By understanding and incorporating these expressions, you can successfully search through a file with ease to get a desired result.

Reflect upon your results of the measurement to ascertain your achievement of the particular course objective.

* How did you do?

Work in progress, as of right now, I am still learning how to use these.

* Is there room for improvement?

Yes.

* Could the measurement process be enhanced to be more effective?

In time, and the usage of these will making the learning of pattern matching that much easier.

* Do you think this enhancement would be efficient to employ?

Yes it would be efficient to employ when searching through a file for a desired result.

* Could the course objective be altered to be more applicable? How would you alter it?

No the course object is applicable to a student, such as I, situation involved Unix.