UNIX Linux Commands

Append

UNIX/

UNIX will be usesimilar. In essenceAIX, and others. source code is opwill be provideduse is increasing

When workinGUI interface (pimand line (variousystem not a line will be preseintuitive. Many son their machinecommand line (m

At the commaencounter, depenThe prompts youthe system ownecommands/configare others, the mo

Korn ShellBourne ShC Shell Pro

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Copyright 2005 CRC Press Lix D

Linux Commands

d to mean both UNIX and Linux, since they are very, Linux is another flavor of UNIX, similar to Solaris,

A great benefit of Linux is that it is open-source (theen for all to see). A UNIX system command reference since it has been widely used for decades and itsglobally.g on a UNIX system, you could encounter either actures/icons/words to point and click on) or a com-s UNIX commands must be typed to work with the

point-and-click operation). Working at the commandnted since the GUI is much easier to use and more

killed UNIX personnel do not have a GUI interface because they much prefer to type commands at theore powerful and versatile and more difficult).nd line, there are various prompts that you couldding on how the owner has configured the system. see are indicative of the type of shell (environment)r is using. The shell allows the user to use a fewurations that are peculiar to that shell. Although therest common prompts/shells you will come across are:

Prompt $ell Prompt $mpt %LC

Although there are many UNIX commands, I will cover those that aremost useful to an investigator and make extensive use of examples toshow how a comFTP commands:

? commandclose, discoUNIX comdelete filenget file1 [fihelphelp commlcd /usr/cemdelete filmget filenamkdir diremput filenaput file1 [fipwdrmdir direcrcv file1 [firemotehelprename filesend file1

AU2768_book.fm Page 218 Tuesday, November 16, 2004 2:17 PM

Copyright 2005 CRC Press L

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mand is most commonly used.

nnect, bye, quitmands such as cd, ls, etc.amele2]

andll_one/log (changes to local machine directory)ename(s).me(S)ctoryme(s)le2]

toryle2] (retrieve from remote). command1 file2[file2]

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UNIX Command Explanation Example End Result

date Writes the current date to the screen date Mon Nov 20 18:25:37 EST 2000sort

infile

f

names

in

whowho am Iclearecho

whateverI type

he screen

banner

big words

letters on the

cat

file1 file2 file3

to the screen first llows it with the

df

system

l print the total kb available, and e system (your

head

file

es of

addresses

to

es of

addresses

to

tail

file

es of

test.txt

to the

es of

test.txt

to the

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Sorts the contents of the input file in alphabetical order

sort names Sorts the contents oalphabetical order

Tells who is logged onto your server whoTells you your user information who am iClears the window and the line buffer clearWrites whatever I type to the screen echo hey you! Writes hey you! to t

Does the same thing as echo only in BIG words

banner hey! Writes hey! in largescreen

Shows the three files in consecutive order as one document (can be used to combine files)

cat cheese milk Prints the cheese fileand immediately fomilk file

Reports the number of free disk blocks df ~df $HOME

Both commands wilspace, kb used, kb%used on the homsystem)

Prints the first 10 lines of the file to the screen

head addresses Prints the first 10 linthe screen

Number of lines can be modified head -25 addresses

Prints the first 25 linthe screen

Prints the last 10 lines of the file to the screen

tail test.txt Prints the last 10 linscreen

Number of lines can be modified tail -32 test.txt Prints the last 32 linscreen

LC

UNIX Command Explanation Example End Result

more

input

Prints to screen whatever is input more

groceries

Will list the

groceries

file to the screen

ls (-

option

-optional)

n files and directories

rectory


ls -l or ll n files and directories rectory in


tory in long formatls -a irectories, including

rrent directory

directories in the

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useful because it only shows one screen at a time

scroll bar continues to the next screenreturn moves one line forwardQ quitsG goes to the end1G goes to the beginningCtrl u moves up _ screenCtrl d moves down _ screenLists all the nonhidden files and directories

ls Lists all nonhiddein the current di

ls bin Lists all nonhiddein thebin directory

Lists all nonhidden files and directories in long format

ls -lll

Lists all nonhiddein the current dilong format

ls -l workll work

Lists all nonhiddein the work direc

Lists all files and directories including hidden ones

ls -a Lists all files and dhidden, in the cu

ls -a temp Lists all files and temp directory

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ls -r Lists all files and directories in reverse alphabetical order

ls -r Lists all nonhidden files and directories in the current directory in reverse alphabetical order

ls -r

abc

Lists all nonhidden files and directories

abc

directory in reverse etical order

ls -t the nonhidden files in the t directory in the order they ast modified from most recent

the nonhidden files in the

work

ry in the order they were last

ed from most recent to last

Note:

Options can

files (including hidden (-a)) in rmat (-l)

| ur files in long format one at a time

>

our listing to a file named

>>

s your filenames to the end of

files

file& lock (a clock) allowing you to

orking

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in the alphab

Lists all nonhidden files in the order they were last modified

ls -t Lists allcurrenwere lto last

ls -t work Lists all directomodifi

be combined using ls. ls -al Lists all long fo

pipe directs the output of the first command to the input of another

ls -l | more Lists yoscreen

Sends the output of a command to a designated file

ls -l > myfiles Prints ymyfiles

Appends the output of a command to a designated file

ls -l >> allfiles Appendthe all

Runs command in the background; you can still work in the window

xclock & Runs xckeep w

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ImportantCharacters Explanation Example End Result

~ Designates the home directory ($HOME)

echo ~ Writes your home directory to the screen

mymonth

Searches the file insensitive matchthe matching linmymonth

Description Example Explanation

Opens filename for editing/viewing in the vuepad editor

none None

Text editor that exists on every UNIX system in the world

none None

Another text editor none NoneCompresses the file to save disk space none None

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uncompress filename

Expands a compressed file none None

awk UNIX programming language none None

Command

eval `resize`

chexp # filename

omputer from starting with nr for 1

ose name starts with r be deleted (infinite)

qstat of the requests invoker of the rint request-name, ner, relative request

uest state (is it

s long format medium-length

sts belonging to the

hown in an extended

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Description Example Explanation

Tells the target computer that the window has been resized during telnet

none None

Keeps the file(s) from expiring (being erased) on the target computer for # days

chexp365 nr*

Keeps the target cdeleting all files year (365 days)

chexp 4095 nr* Makes all files whnr never expire o

Displays the status of a process that has been submitted the Network Queuing System (basically a batch job)

qstat Shows the status submitted by thecommand will prequest-id, the owpriority, and reqrunning yet?)

qstat -a Shows all requestqstat -l Shows requests inqstat -m Shows requests in

formatqstat -u bob Shows only reque

user bobqstat -x Queue header is s

format

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Command Description Example Explanation

xterm Opens a new window(x-terminal) for you

xterm This opens another window like the one you are currently working in.

xterm -optionxterm +optionNote: Using xtermstrongly recomm

xterm -help s availablexterm -e program

indow and executes rog.exe from that ou may still work in dow

xterm -sb n the right side of the ng past lines in the

Note: When clickscrolls down, thethe scroll bar to tdown.

xterm -sl number

00 lines of work once the immediate an be accessed using

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to work-option sets the option+option resets the option to default will eliminate desktop clutter. I end learning to use it in your scripts.Displays the xterm options xterm -help Shows the optionExecutes the listed program in the new xterm window; when the program is finished, the new xterm window goes away

xterm -e myprog.exe

Opens an xterm wthe program mypwindow so that yyour present win

Opens an xterm that saves a set number of lines when they go off the top of the page and makes them accessible with a scroll bar

xterm -sb Puts a scroll bar opage for reviewiwindow

ing in the scroll bar, the left button right scrolls up, and the middle snaps he mouse position for dragging up and

Specifies the number of lines to be saved once they go off the top of the screen (default is 64)

xterm -sl 1000 xterm will save 10it has moved offviewing area; it cthe scroll bar

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xterm -geom xxy+px+py

Option allows you to specify the size x pixels by y pixels and placement position x by position y of the new window when it opens

xterm -geom 80x80+0+50

First command will open a window 80 pixels wide by 80 pixels tall and position its top left-hand corner at 0 pixels to the right of the left edge and

m the top of the

Note: The size of position, so if yoscreen, it will po

ill open a window 35 pixels tall and t-hand corner 300 edge and 500 pixs

. will make a 5 by 5

ion its topt the top left-hand en.promise size when

xterm -title label

ndow with the title whatever follows

xterm -(areas) color lor

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Position +0+0 is the top left-hand corner of the screen; and the bottom right is approx. +1200+1000 depending on the resolution

50 pixels down froscreen

the window takes precedence over u position it too close to the side of the sition at the edge with the correct size.

xterm -geom 10x35+300+500

Second command w10 pixels wide by position its top lefpixs from the left down from the top

xterm -geom 5x5+0+0

The third commandwindow and positleft-hand corner acorner of the scre

xterm will not compositioning.

Allows you to label your windows top title bar

xterm -title SCRIPTS

Opens an xterm wiSCRIPTS (default isthe -e option)

Allows you to modify different colors in your xterm window

xterm -bg white First command setsthe background coto white

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Command Description Example Explanation

xterm -bd huntergreen

Second command sets the window border color to huntergreen

xterm -fg red The third command window sets the

xterm -fn font rr18 (default is

xterm -iconic conic form with the

Note: Options c

Command

alias dir ls btain a directory rd in place of dir. erefore, now when

and line, it would ormally do.)

aliasunalias dir mand to be used

alias h history f the entire mmand gives a list ped on the system g on how history

tar -cvf a:archive stores the resulting

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text color to redSets the font in the new xterm window xterm -fn

courr18 Sets the font to coufixed)

Starts the new xterm as an icon (double-click to maximize)

xterm -iconic -title xyz

Opens an xterm in ititle xyz

an be combined using xterm.

Description

Enables typing of either dir or ls to olisting. (Note: I can substitute any woI can even use the word mouse. ThI type the word mouse at the commdo what the command ls would n

Displays all defined aliases.Now dir will no longer work as a comin place of ls.

Now I only have to type h instead ocommand history. The history coof the commands that have been ty(a certain number of them, dependinwas configured).

. Backs up the current directory (.) and archive on the diskette in a:

s LLC

Command Description

tar -cvf a:archive *.doc Backs up every file with the .doc suffix.tar -cvf a:archive - Used when you want to type filenames from the keyboard

ame on a separate line.

tar -tf a:archive | m tly contained in the

find / -ctime -7 > ed in the last 7 days. st.

tar -cvf a:archive -find / -ctime -7 | t ove

ng

dfdugrep -i ^ftp /etc/i ftp services:find / -name *s -p ectory

ing with and s and print

find / -name core ys since last access and portant since they

he failure of a system or system.

find / -ctime -2 -p en changed fewer than

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(standard input). Type each filen^Z indicates end of list.

ore Produces a list of all files currenarchive.

weeklist Identify any files that have changPlace these filenames in weekli

< weeklist Backup all files in weeklist.ar -cvf a:archive - Does the same thing that the ab

2 commands do, but does it usia pipe (the | symbol).

Disk space usage on a file systemDisk space used by a directory

netd.conf Check to see if you are running rint Begins the search at the root dir

(/) and look for anything (*) endit to the screen.

-atime +7 -exec rm -f {}|; Finds all core files more than 7 daremoves them. Core files are imcontain information relating to tan application running on that

rint Returns all the files that have be2 days ago

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Command Description

find /users/jake -exec chown jake {} \; Makes the user jake the owner of the directory/users/jake and everything underneath it

find / -nogroup -p ot listed in /etc/groupfind / -nouser -pr ot listed in /etc/passwdfsck sistency of the information

systems listed in /etc/fstab.

ot)ems in some flavors

ftp o open communications to llows transfer of files to/lows (type the words in

key>

1 is the name of the system unications with>

our userID on TMG1>

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rint Finds file owned by a user nint Finds files owned by a user n

Examines disks to ensure conthey contain. Checks all file

0 = successfulfsck -p /dev/rra1h (in rc.boBSD: /etc/fstab /etc/filesystATT: /etc/checklist

File Transfer Protocol: used tanother computer system. Afrom that system. Use as folitalics):

ftp open(to) TMG1

Documents

UNIX Linux Commands