A-Z Index of the Linux BASH basic commands

[cyclops07]

Have anyone put this on?....

just list everything down.. maybe some commands r n't here..

alias Create an alias
awk Find and Replace text within file(s)

break Exit from a loop
builtin Run a shell builtin

cal Display a calendar
case Conditionally perform a commandcat Display the contents of a file
cd Change Directorychgrp Change group ownershipchmod Change access permissionschown Change file owner and group
chroot Run a command with a different root directorycksum Print CRC checksum and byte counts
clear Clear terminal screen
cmp Compare two files
comm Compare two sorted files line by line
command Run a command - ignoring shell functions
continue Resume the next iteration of a loopcp Copy one or more files to another locationcron Daemon to execute scheduled commands
crontab Schedule a command to run at a later timecsplit Split a file into context-determined pieces
cut Divide a file into several parts

date Display or change the date & time
dc Desk Calculator
dd Data Dump - Convert and copy a file
declare Declare variables and give them attributesdf Report filesystem disk space usagediff Display the differences between two filesdiff3 Show differences among three filesdir Briefly list directory contents
dircolors Colour setup for `ls'dirname Convert a full pathname to just a path
dirs Display list of remembered directories
du Estimate file space usage

echo Display message on screen
ed A line-oriented text editor (edlin)
egrep Search file(s) for lines that match an extended expression
eject Eject CD-ROM
enable Enable and disable builtin shell commands
env Display, set, or remove environment variables
expand Convert tabs to spaces
export Set an environment variable
exec Execute a command
expr Evaluate expressions
eval Evaluate several commands/arguments

factor Print prime factors
false Do nothing, unsuccessfully
fdformat Low-level format a floppy disk
fdisk Partition table manipulator for Linux
fgrep Search file(s) for lines that match a fixed string
find Search for files that meet a desired criteria
fmt Reformat paragraph text
fold Wrap input lines to fit in specified width
for Expand words, and execute commands
format Format disks or tapes
free Display memory usage
function Define Function Macros

gawk Find and Replace text within file(s)
getopts Parse positional parameters
grep Search file(s) for lines that match a given pattern
groups Print group names a user is in
gzip Compress or decompress named file(s)

hash Remember the full pathname of a name argument
head Output the first part of file(s)history Command History
hostname Print or set system name

id Print user and group id's
if Conditionally perform a command
import Capture an X server screen and save the image to file
info Help info
install Copy files and set attributes

join Join lines on a common field

kill Kill a process

less Display output one screen at a time
let Perform arithmetic on shell variables
ln Make links between files
local Create variables
logname Print current login name
logout Exit a login shell
lpc Line printer control program
lpr Off line print
lprint Print a file
lprintd Abort a print job
lprintq List the print queue
lprm Remove jobs from the print queue
ls List information about file(s)

m4 Macro processor
man Help manual
mkdir Create new folder(s)
mkfifo Make FIFOs (named pipes)
mknod Make block or character special files
more Display output one screen at a time
mount Mount a file system
mtools Manipulate MS-DOS files
mv Move or rename files or directories

nice Change job scheduling priority
nl Number lines and write files
nohup Run a command immune to hangups

passwd Modify a user password
paste Merge lines of files
pathchk Check file name portability
popd Restore the previous value of the current directory
pr Convert text files for printing
printcap printer capability database
printenv Print environment variables
printf Format and print data
pushd Save and then change the current directory
pwd Print Working Directory

quota Display disk usage and limits
quotacheck Scan a file system for disk usage
quotactl Set disk quotas

ram ram disk device
read read a line from standard input
readonly Mark variables/functions as readonly
remsync Synchronize remote files
return Exit a shell function
rm Remove files
rmdir Remove folder(s)

screen Terminal window manager
sdiff Merge two files interactively
sed Stream Editor
select Accept keyboard input
seq Print numeric sequences
set Manipulate shell variables and functions
shift Shift positional parameters
shopt Shell Options
sleep Delay for a specified time
sort Sort text files
source Run commands from a file `.'
split Split a file into fixed-size pieces
su Run a command with substitute user and group id
sum Print a checksum for a file
symlink Make a new name for a file
sync Synchronize data on disk with memory

tac Concatenate and write files in reverse
tail Output the last part of files
tar Tape ARchiver
tee Redirect output to multiple files
test Evaluate a conditional expression
time Measure Program Resource Use
times User and system times
touch Change file timestamps
trap Run a command when a signal is set(bourne)
tr Translate, squeeze, and/or delete characters
true Do nothing, successfully
tsort Topological sort
tty Print filename of terminal on stdin
type Describe a command

ulimit Limit user resources
umask Users file creation mask
umount Unmount a device
unalias Remove an alias
uname Print system information
unexpand Convert spaces to tabs
uniq Uniquify files
units Convert units from one scale to another
unset Remove variable or function names
unshar Unpack shell archive scripts
until Execute commands (until error)
users Print login names of users currently logged in
uuencode Encode a binary file uudecode Decode a file created by uuencode

v Verbosely list directory contents (`ls -l -b')
vdir Verbosely list directory contents (`ls -l -b')

watch Execute/display a program periodically
wc Print byte, word, and line counts
which Show full path of commands
while Execute commands
who Print all usernames currently logged in
whoami Print the current user id and name (`id -un')

yes Print a string until interrupted

.period Run commands from a file
### Comment / Remark

[s0nIc]

hahah wow.. tnx.. just what i needed

[sniper001]

Yeah, pretty good and useful. Thx

[AngryBob]

spanks [BUMP]

[tyger_claw]

****... that's a lot of time invested.....

thanks for the list.....
now to cut, paste, and print

[Mucolaca]

lol yeah i needed that thanks

[cwk9]

Perfect just what a Linux newbie like me needs.

[Tuskin]

no chat commands?! hahaha its a good overall idea of useful commands

[Query]

It give me a good idea.... thanks...

[ahmedmamuda]

Basic UNIX hacking

UNIX is probably the most commonly used operating system on Telenet, and is the easiest to hack, atleast to me, since it doesn't record any bad login attempts. You know you've found a UNIX system when it gives you a "Login" prompt, and then a "Password" prompt. To get in you should first try the default logins.(Listed below.) If these don't work try some of the passwords listed in Section M. If these don't work try to find backdoors. These are passwords that may have been put in to allow the programmer (or someone else who could be in a position to make a backdoor) to get access into the system. These are usually not known about by anyone but the individual who made it. The Login (usually the account holders name) has 1-8 characters and the Password is 6-8 characters. Both can be either letters or numbers, or a combination of the two.
Once you get in, you should get a "$" prompt, or some other special character like it. You should only use lower case letters when hacking UNIX, this seems to be standard format. If you type "man [command]" at the prompt, it should list all of the commands for that system. Anyway, here are the default Logins and Passwords:


Login: Password:

root root
root system
sys sys
sys system
daemon daemon
uucp uucp
tty tty
test test
unix unix
unix test
bin bin
adm adm
adm admin
admin adm
admin admin
sysman sysman
sysman sys
sysman system
sysadmin sysadmin
sysadmin sys
sysadmin system
sysadmin admin
sysadmin adm
who who
learn learn
uuhost uuhost
guest guest
host host
nuucp nuucp
rje rje
games games
games player
sysop sysop
root sysop
demo demo


Once you are in, the first thing that you need to do is save the password file to your hard drive or to a disk. The password file contains the Logins and Passwords. The passwords are encoded. To get the UNIX password file, depending on what type of UNIX you are in, you can type one of the following things:

/etc/passwd
or
cat /etc/passwd

The first one is the standard command, but there are other commands as well, like the second one. Once you get the password file, it should look like this:


john:234abc56:9999:13:John Johnson:/home/dir/john:/bin/john


Broken down, this is what the above password file states:


Username: john
Encrypted Password: 234abc56
User Number: 9999
Group Number: 13
Other Information: John Johnson
Home Directory: /home/dir/john
Shell: /bin/john


If the password file does not show up under one of the above two commands, then it is probably shadowed.
The following definition of password shadowing was taken from the alt.2600 hack faq:
"Password shadowing is a security system where the encrypted password field is replaced with a special token and the encrypted password is stored in a seperate file which is not readable by normal system users."
If the password file is shadowed, you can find it in one of the following places, depending on the type of UNIX you are using:


UNIX System Type: Path: Token:

AIX 3 /etc/security/passwd !
or /tcb/auth/files/<first letter of #
username>/<username>

A/UX 3.Os /tcb/files/auth/*

BSD4.3-Reno /etc/master.passwd *

ConvexOS 10 /etc/shadpw *

Convex0S 11 /etc/shadow *

DG/UX /etc/tcb/aa/user *

EP/IX /etc/shadow x

HP-UX /.secure/etc/passwd *

IRIX 5 /etc/shadow x

Linux 1.1 /etc/shadow *

OSF/1 /etc/passwd[.dir|.pag] *

SCO UNIX #.2.x /tcb/auth/files/<first letter of *
username>/<username>

SunOS 4.1+c2 /etc/security/passwd.adjunct ##

SunOS 5.0 /etc/shadow

System V 4.0 /etc/shadow x

System V 4.2 /etc/security/* database

Ultrix 4 /etc/auth[.dir|.pag] *

UNICOS /etc/udb *


Some passwords can only be used for a certain amount of time without having to be changed, this is called password aging. In the password file example below, the "C.a4" is the password aging data:


bob:123456,C.a4:6348:45:Bob Wilson:/home/dir/bob:/bin/bob


The characters in the password aging data stand for the following:


1. Maximum number of weeks a password can be used without changing.
2. Minimum number of weeks a password must be used before being changed.
3&4. Last time password was changed, in number of weeks since 1970.


The password aging data can be decoded using the chart below:

Character: Number:

. 0
/ 1
0 2
1 3
2 4
3 5
4 6
5 7
6 8
7 9
8 10
9 11
A 12
B 13
C 14
D 15
E 16
F 17
G 18
H 19
I 20
J 21
K 22
L 23
M 24
N 25
O 26
P 27
Q 28
R 29
S 30
T 31
U 32
V 33
W 34
X 35
Y 36
Z 37
a 38
b 39
c 40
d 41
e 42
f 43
g 44
h 45
i 46
j 47
k 48
l 49
m 50
n 51
o 52
p 53
q 54
r 55
s 56
t 57
u 58
v 59
w 60
x 61
y 62
z 63


Now, explore the system freely, be careful very carefull not to get caught,have fun! and Dance around the system