Tutorial of Unix Command & shell script S 5027

TUTORIAL OFUNIX COMMAND & SHELL SCRIPTS 5027

Professor: Dr. Shu-Ching ChenTA: Hsin-Yu Ha

OUTLINE Log in Unix Basic Commands Shell script

OUTLINE Log in Unix Basic Commands Shell script

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For exmaple, Steven Jackson with PID 1234567 should have password s1234567j

OUTLINE Log in Unix Basic Commands Shell script

COMMANDS ABOUT FILES (1) ls : list the contents of your current directory.

Format Options

-a : list all the files include the hidden ones -l : list not only the files name but also the related info -t : list the contents by modified date

ls [option] [directory][file]

COMMANDS ABOUT FILES (2) File permission

Field1 : A set of ten permission flags Field2 : link count Field3 : owner of the file Field4 : associated group of the file Field5 : size Field 6-8 : Last modification date Field9 : file name

COMMANDS ABOUT FILES (3) chmod : change the permission flags of the

files Format

Example chmod g+w myfile chmod g-rw myfile chmod u=rw go= myfile chmod –R g+rw myfile

chmod [option] [types][+/-][types of permission] filename

COMMANDS ABOUT FILES (4) pwd : print out the current working directory cd : change directory

cd . (.) means the current directory C (..) means the parent of current

directory Cd cd with no argument will return you to

your home directory

cd .cd ..cd

COMMANDS ABOUT FILES (5) cp : copy files

Format Options

-i : It can be used to avoid overwriting the original file -r : Copy the folder and all the files and subfolders

under it. mv : move a file from one place to another or

rename a file. Format

cp [option] File1 File2

mv File1 File2

COMMANDS ABOUT FILES (6) mkdir : making directory

Format rm : remove files or directories

Format Option

-i : ask before actually delete -r : delete the folders and all the files and subfolders

under it

mkdir Directory_name

rm [option] file1 file2 file3…

COMMANDS ABOUT FILES (7) test : A command in Unix that evaluates conditional

expressions. Format or The functions will return true if the object exist or the

condition specified is true. File functions

-d Filename : Filename is a directory -s Filename : Filename has a size greater than 0 -f Filename : Filename is a regular file

test expression [ expression ]

COMMANDS ABOUT FILE’S CONTENTS (1) cat : display the contents of a file on the screen

Format head : display the first ten lines of a file to the

screen Format

tail : display the last ten lines of a file to the screen Format

cat file1

head –n file1

tail –n file1

COMMANDS ABOUT FILE’S CONTENTS (2) wc : word count

Format Options

-w : find out how many words the file has -l : find out how many lines the file has

wc [options] file

COMMANDS ABOUT FILE’S CONTENTS (3) grep : It searches files for the specified words or

patterns. Format: Options:

-c : Display the number of columns which satisfied the pattern.

-i : Ignore case distinctions in both the PATTERN and the input files.

-v : Invert the sense of matching, to select non-matching lines.

grep [options] [pattern] file

Pipe : It cause the execution of multiple processes from one single line

A | B | C

COMMANDS ABOUT FILE’S CONTENTS (4) Redirection

> and >> can be used on the output of most commands to direct their output to a file.

Examples

COMMANDS ABOUT TEXT PROCESSING (1) sort : sort lines of a text file or files

Default : sort without any option will sort the file alphabetically

Format uniq : remove duplicate adjacent lines from

sorted file.

sort [option] file

COMMANDS ABOUT TEXT PROCESSING (2) sed: One ultimate stream editor

Detail Tutorial : http://www.grymoire.com/Unix/Sed.html

Important function -> Substitution Format : sed 's/term1/term2/g‘ filename

COMMANDS ABOUT TEXT PROCESSING (3) cut : extract sections from each line of a file.

Format Option

-c : character -f : field -d “:” : delimiter (default is a tab)

Range N-M N- -M

cut [options] [range] filename

OUTLINE Log in Unix Basic Commands Shell script

SHELL SCRIPT INTRO (1) Scripts are collections of commands that are

stored in a file.

Detail Tutorial http://www.freeos.com/guides/lsst/

Basic Vi commands vim filename i : switch to the editing(insert) mode Esc +:q! Leave the vim program without saving

the file Esc +:w Save the file Esc +:wq Save the file and leave the vim program

SHELL SCRIPT INTRO (2) First shell script

Note that to make a file executable, you must set the eXecutable bit, and for a shell script, the Readable bit must also be set.

SHELL SCRIPT INTRO (3) Variable

SHELL SCRIPT INTRO (4) IF LOOP

SHELL SCRIPT INTRO (5) For Loop

SHELL SCRIPT INTRO (6) Useful concept $( commands)