UnixAndShellScripting.txt

ls						------> to list all files in curr dir
ls -ltr / ls -l -t -r 	------> to details view of all files

External Commands -> executes by Kernel (cat)
Internal Commands -> executes by shell (ls,type,pwd,eco,cd)

pwd	------> to see curr directory

bin	--> user binary
sbin	--> system binary

cd .. ---> to return back in directory

cd /etc --->all the software will install at this location

cal 		---> For calander
cal 2022	---> to see year of calander

date		---> to see curr date nd time
date +%d 	---> display only date value
date +%D 	---> display date in mm/dd/yyyy
date +%F    ---> yyyy-mm-dd
date +%H 	---> hour value
date +%J	---> no. of pass day in year
date +%m 	---> month
date +%M 	---> minute
date +%S	---> sec
date +%N 	---> Nano Sec

passwd 		---> to change the password

who 		---> shows the all users
who am i 	---> your login
w 		---> gives complete details
logname 	---> account / user which are currenty using

last 		---> previous history of login logut reboot datails


cal -1		---> 1 CURR MONTH Calander
Cal -3		---> shown 3 month calander (prev , curr, next)
cal -s 	---> **shows related arguments and commands
cal -m 	---> **shows related arguments and commands
cal -j 	---> shown 1 month calander in the from of no. of days 
cal -y 	---> shown whole year calander

date +%d	-> curr_date 13
date +%D	-> mm/dd/yy
date +%F	-> yyyy-mm-dd
date +%H	-> hour 24-hour
date +%I	-> Shows hour in 12-hour format [11]
date +%j	Displays the day of the year [001 – 366]
date +%m	month
date +%M	min
date +%S	sec
date +%N	nano sec
date +%Y	year
date +%Z	zone

tty		--->prints the file name of the terminal connected to standard input.
stty		--->used to change and print terminal line settings

man mkdir
echo "Welcome to the session"			---> will show the welcome
echo "Welcome to the session" > myfile.txt	---> will copy the text in myfile.txt if not exist it will create a file and copy the text
cat myfile.txt 				---> will show the content of file


*********In linux all are process/file.


Prefix
_	-> Regular file
d	-> Directory file
c	-> Charater file
b	-> Block file
n	-> Named Pipes or FIFO
p	-> Link
s	-> Socket


if . prefix is the used to make file is hidden file.	TO SEE use --> ls -ltra

df		-> displays the amount of disk space available on the filesystem with each file name's argument
df -a		-> all info
df -a /home	-> all info of home
df -h		-> print size in powers of 1024
df --help	-> to see the more about df

du		-> disk uses
du -h /home	-> print size in human readable forment
du -g /home	-> n/a
du -a /home	-> print all info
du -k /home	->



uname		-> unix system machine
uname -a 	-> complete info
uname -n	print the network node hostname
uname -s	print the kernel name
uname -m	print the machine hardware name
uname -p	print the processor type (non-portable)
uname -i	print the hardware platform (non-portable)


cd ..	-> go to prev dir
cd -	-> go to prev cmd dir
cd / 	-> go to root dir
cd ~	-> go to home dir  /

mkdir -p file_name -------> will crete file if exits not will create

man rmdir	--> it will show all detials about the rmdir cmd

rmdir		--> will remove dir if it is empty
rm -rf 	--> focefully delete

ls
ls -t	-> only file in reverse
ls -r	-> in revesre wise show
ls -R	-> tree wish
ls -c 	-> col wise
ls -a 	-> to see all file
ls -i	-> 
ls -v 	-> version wise
ls -u	-> last excuted wise

ls -ltra	-> see all info
ls -slrta	-> sort size wise

****************************************************************************************************************************************

ls -t
ls -r
ls -R
ls -c
ls -x
ls -X
ls -a
ls -v
ls -i
ls -u
ls *
ls -L
ls -A
ls -s
ls -S
ls -p
ls -n
ls -h
ls -F
ls -I

touch x.txt
touch y.so
touch z.xl
touch 04365465z.xl
touch file{1,2,3,4,5}
echo "This is file1" > file1
echo "This is file2" > file2

cat file1	//for displaying
cat file2

cat file1 file2 > file3	//for copy

display:
cat file2
cat file3
cat file1 file2

cat file1>file2	//for copy
cat file1 file2
cat  > file1
cat file1
cat file1 >> file2	// for append
cat file2

display: split horigentally
more file3		from start
less file3		from end
head test.txt		10 line from start
head -n 3 test.txt	3 line from start
tail text.txt		10 line from end
tail -n 3 text.txt	3 line from end

display Split vertically:
cut -c 5-12 15-18 test.txt
cut -d " " -f 1,4 file1.txt	// 1 and 4
cut -d " " -f 1-4 file2.txt	// 1 to 4
who | cut -d " " -f 1		
who | cut -d " " -f 1,2
ls -ltr | cut -c 3-12


Paste :
paste -d " " file1.txt file3.txt

ls -ltr | tee file_ls.txt 	=> all the data will go at tee file i.e it will store the data 

ls -ltra | head -n 2	==> it will show 2 line from start 


delete:
rm file1 file3



WC -LC FILE3	ERROR
LP -W
LP -O NOBANNER
LP -P LIST
LP -D PRINTER
LP -N NUM
LP -Q LEVEL


PIPING COMMANDS :
WC -1 | LP	// WORD COUNT
WHO | WC -1
LS | WC -1 > LINECOUNT
CAT FILE3 | MORE
WC < FILE3
CAL > FILE3
CAT A.TXT | MORE | WC -L > BB
CAT XYZ ABC > OUTFILE 2>&1
CAT XYZ ABC > OUTFILE 2> ERRFILE
WC TEST.TXT >> DEF


vi text.txt ====> to create a file with text end quit from editor mode esc :qw!



translating character :
man tr   
echo "linux        server" | tr -s " " ","	=> linux,server
head file1.txt | tr '[a-z]' '[A-Z]'		=> will change the all later in upper case of file1 

campare:
cmp file1.txt file3.txt => it will display the line num and char num where the difference will found // only file

difference :
diff file1.txt file3.txt => it will show whole difference in files

alias fr='cal' => it will display cal for cal and fr both
unalias fr='cal' 	=> to remove the alias


Search for file:
find /home -name file1.txt	=> to find a file and their path
find $HOME -iname file1.txt	=> it will search for all file with same name but diff case

find / -type f -name ".txt" 	=> all file come with .txt extension

search for dir:
find /home -type d -name edureka

cat - it is used to displaay the contents of one or multiple text files, combine files by appending one file’s contents to the end of another file, and create new files.
	cat [OPTIONS] [FILE_NAMES]
	cat file1 name > file2 name	-> to copy content of file 1 in file 2
	cat file1 name >> file2 name	-> to append the content of file1 in the end of file2
	cat -n file name		-> to display with numberwise
	cat -t file name		-> to seprate with tab and spaces
	


File Security : control accress to files and directories. (bu ownership / permission)
Types of Access :
	1. User/owner Permission (u)
	2. Group Permissions (g)
	3. Othe/Public Permissions (o)
	4. All (a)


chmod +rwx	-> filename to add permissions
chmod -rwx	-> directoryname to remove permissions
chmod +x	-> filename to allow executable permission
chmod -wx	-> to remove write and executable permission



	default octal value (4+2+1=7) highest level of permission
R(0-7)	->4 
W(0-7)	->2
X(0-7)	->1

0 --- (Noting is there from w r x)
1 --X
2 -w-
3 -wx
4 r--
5 r-x
6 rw-
7 rwx


      ogp
chmod 100 test.txt

chmod u+w a.txt
chmod u+x test.txt	-> By using alphabet
chmod o+wx,u-x,g=r-x test.txt

chmod -R 777 test.txt	recursive permission (it will set permission of all same under the dir)





cat /etc/passwd/	-> will show all users

useradd 	//It will add user when u are in root dir to swich in root ==> sudo su -
useradd -m devops_unix	-> add a user with name devops unix
passwd devops_unix	-> change the password

groupadd devops_group	=> to add in group

chgrp devops_group username_group_file.txt	=> it will work in root // to change the group
chown devops_unix username_group_file.txt	=> 

vi file name-> used to view and edit

000-777	=> for dir
000-666	=> for files

umask test.txt -> view or to set the file mode creation mask, which determines the permissions bits for newly created files or directories.

info umask -> gives information about recentely created file
man umask -> user manual


mesg : is used to msg to other users
wall
talk
write
mail
news
ping

uptime : see all about the machine like no. of users and time and all.
hostname : to see the hostname
ifconfig : used to configure the kernel-resident network interfaces.
nslookup sitename : will change in ip address (hostname to ip and ip to hostname)

netstat => will show all the connection of tcp and udp


Editors : ex, ed, sed, gEdit, emacs, nano, vi, vim, etc.
The best way of using screen-oriented text editor is vi and an improved version of vi editor is called vim.



***********vi file_name => to open or create file.********

The editor vi has theree modes of operations.
First operation = command mode.
Second operation = Input mode.
Third Operation = Exclusive mode.
Command Mode is the default mode.
For invoking input mode we can use "ESC + i"
For performing the tasks like exit , saving , substitue -- press ":" -
For saving . we will use "ESC + :wq!"
With out saving. we will use "ESC + :wa!" 
for appending something wee need to press " Esc + a".
for moving the cursor left of right . you can use left arrow key or right arrow key of h or hackspace.
for moving the cursor up === press "ESC + k"
for moving the cursor down === press "ESC + j"
for revert back any changes undo === press "ESC + u"
for redu === press ctrl + r.
CTRL + d move forword 1/2 screen.
CTRL + f move forword one full scrren
CTRL + u move backword 1/2 screen.
CTRL + b move backword one full scrren	
CTRL + e move screen up 1 line
CTRL + y move screen down 1 line
To do this, press Esc , type the line number, and then press Shift-g . If you press Esc and then Shift-g without specifying a line number
positition cursor at begining of line -- ESC + 0
position cursor at end of line == ESC + $

Go at line n. 5 : "ESC+ :5
use "ESC + x" to remove anything
Esc + nx to delete n element
Esc + dd to delete whole line
ESC + D
ESC + d0
Esc + dw
FOR deleting two line ESC + 2dd

For search "ESC + /word" "ESC+ ?word"

Replacemnt and substitue :

:%s/FOR/FOR/g

for copy : ESC + :8 co 10

*****sed_commmands*******
it is stream oriented editor.

sed '3d' myfirst_regex_sed_file	=> delete 3rd line temporary.
sed -i '3d' myfirst_regex_sed_file	=> it will delete 3rd line from the original file.
sed '$d' myfirst_regex_sed_file 	=> delete last line
sed '2,4d' myfirst_regex_sed_file	=> delete from line 2 to 4
sed '1d;$d' myfirst_regex_sed_file	=> delete first and last line.
sed '/^w/d' myfirst_regex_sed_file 	=> delete which will starts with w.
sed '/s$/d' myfirst_regex_sed_file 	=> delete ending with s
sed '/[sn]$/d' myfirst_regex_sed_file	=> delete ending with s and n both
sed '/[A-Z]$/d' myfirst_regex_sed_file	=> it will delete a line which have all capital latters
sed '/unix/d' myfirst_regex_sed_file		=> delete a line having unix word
sed '/unix\|u/d' myfirst_regex_sed_file
sed '1,/Akrisht/d' myfirst_regex_sed_file	=> delete startig from 1 to till find Akrisht


Shell Script : Runnig commands in ordered way is call shell script.

types : born sell c sell bash cell 

# is used for commment
extension => .sh

Shebangline	#!/bin/sh	=> optional

To run :=> ./filename.sh OR sh filename.sh

ls -ltr &	=> run in background
fg %1 		=> for foreground job

sed 's/Peach/Grapes/g' fruit_prices.txt 	==> replace peach to grapes
sed -n '/0\.[0-9][0-9]$/p' fruit_prices.txt	==> show only 0-.99


**top***ps**
**free***

***awk command*****

Fruit		Price
Banana 	0.90	
Peach 		0.56
Kiwi 		1.30
Pineapple	1.25
Apple 		0.99
Mango		2.20



awk '{print ;}' fruit_prices.txt			=> will print whole table 
awk '{print $1 ;}' fruit_prices.txt 			=> will print first colomn
awk '{print $2 ;}' fruit_prices.txt 			=> will print second colomn


awk '{print $1, $2, S3,"*";}' fruit_prices.txt
Fruit Price  *
Banana 0.90  *
Peach 0.56  *
Kiwi 1.30  *
Pineapple 1.25  *
Apple 0.99  *
Mango 2.20  *




**************hello.sh*****************
#!/bin/bash

# This is my first shell script

echo "Hello World!"

echo "Enter your name :"

read name

echo "your name is : " $name



****************firstShellScript*******************************

#!/bin/sh

awk '/ *\$[1-9][0-9]*/ {print $0. ;}/*\$0\.[0-9][0-9] */{print ;}' fruit_prices1.txt



************************************************************
Shell Script Operations :

echo My salary is $5000
My salary is 000

echo My salary is \$5000
My salary is $5000

echo Hello\; World
Hello; World

echo "This will print \
as two lines"
This will print as two lines

akshrits@CGLX-LPT-159U:~$ var='cal'
akshrits@CGLX-LPT-159U:~$ var=`cal`
akshrits@CGLX-LPT-159U:~$ echo $var
November 2022 Su Mo Tu We Th Fr Sa 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

akshrits@CGLX-LPT-159U:~$ DATE='date'
akshrits@CGLX-LPT-159U:~$ echo $DATE
date
akshrits@CGLX-LPT-159U:~$ DATE=`date`
akshrits@CGLX-LPT-159U:~$ echo $DATE
Thursday 17 November 2022 10:49:49 AM IST

akshrits@CGLX-LPT-159U:~$ echo "6*4" | bc; echo "6+4"| bc;echo "6-4" | bc;echo "6/4"|bc;echo "6%4" |bc
24
10
2
1
2

akshrits@CGLX-LPT-159U:~$ echo "6*4" | bc; echo "6/7" | bc;
24
0

akshrits@CGLX-LPT-159U:~$ echo "5-2;last+6" | bc;
3
9

akshrits@CGLX-LPT-159U:~$ x=`echo "15-4" | bc`; echo $x
11

akshrits@CGLX-LPT-159U:~$ echo "sqrt(10)" | bc;
3

akshrits@CGLX-LPT-159U:~$ echo "scale=3;sqrt(10)" | bc;
3.162

akshrits@CGLX-LPT-159U:~$ echo "obase=16;128" |bc;	#decimal to hexadecimal
80

akshrits@CGLX-LPT-159U:~$ echo 'ibase=16;obase=A;80' |bc;	#hexadecimal to decimal
128

akshrits@CGLX-LPT-159U:~$ echo 'obase=2;128' |bc;	#decimal to binary
10000000

akshrits@CGLX-LPT-159U:~$ echo 'ibase=2;obase=A;10000000' | bc;	#binary to decimal
128

akshrits@CGLX-LPT-159U:~$ echo "10^2" | bc;
100

akshrits@CGLX-LPT-159U:~$ expr length Linux	#length of linux
5
akshrits@CGLX-LPT-159U:~$ expr length Linux\ System
12

akshrits@CGLX-LPT-159U:~$ expr substr Linuxserver 5 6;	#give sub string of len 6 which starts with 5 character
xserve

akshrits@CGLX-LPT-159U:~$ expr index Linux nux;	#find and give the index of substr in str. if not found it will show 0
3

akshrits@CGLX-LPT-159U:~$ a=10; b=20;
akshrits@CGLX-LPT-159U:~$ echo `expr $a+$b`
10+20
akshrits@CGLX-LPT-159U:~$ echo `expr $a+$b` |bc;
30

************************************first_if_else_script.txt**********************

#! /bin/bash

var1=10
var2=20

if [ $var1 -eq 10 ] ; then

echo "command was successful.";

else

echo "An error was encountered."
exit

fi		#fundamental control statement that allows Shell to make decisions and execute statements conditionally.

o/p => command was successful.



***************************second_script***********************
#! /bin/bash

echo "Please enter the value of var"
read var

if [ $var -ne 10 ] ; then
	echo "An error was encountered."
	exit

fi

echo "command was successful."



*************************modified_second_script********************
#! /bin/bash

echo "Please enter the value of var1"
read var1

if [ $var1 -ne 10 ] ; then
	echo "An error was encountered."
else
	echo "Command was successful."
fi

echo "Please enter the value of var2"
read var2

if [ $var2 -gt 10 ] ; then
	echo "value is greater than 10.";
else 
	echo "value is less than 10."
fi

echo "Please enter the value of var3"
read var3

if [ $var3 -lt 10 ] ; then
        echo "value is less than 10.";
else 
        echo "value is greater than 10."
fi




****************case in shell script (fruit.sh)***********************
#! /bin/bash 

FRUIT=kiwi

case "$FRUIT" in
	apple) echo "Apple is very tasty" ;;
	banana) echo "I like banana nut bread" ;;
	kiwi) echo "New zeeland is famous for kiwi" ;;
esac



****************while_loop.sh***************************
#! /bin/bash

x=0

while [ $x -lt 10 ]
do
	echo $x
	x=`echo "$x +1" | bc`

done

o/p=> 
0
1
2
3
4
5
6
7
8
9

**************************break_nested_loop.sh**********************
#! /bin/bash

for i in 1 2 3 4 5
do 
	mkdir -p /home/akshrits/shell_scripts/backup/docs/chapter0${i}
	if [ $? -eq 0 ] ; then
		for j in docs c h m pl sh
		do 
			cp $HOME/docs/ch0${i}/*.${i} /home/akshrits/shell_scripts/back/docs/chapter0${i}
		if [ $? -ne 0 ] ; then break 2 ; fi
		done
	else
		
		echo "Could not make backup directory"
	fi

done	

*******************command_line_name(taking input using for loop)*********************
#! /bin/bash

for arg in "$@"		#take input using for loop
do
	index=$(echo $arg | cut -f1 -d=)
	val=$(echo $arg | cut -f2 -d=)
	
	case $index in
		x) x=$val;;
		y) y=$val;;
		*)
	esac
done
((result=x+y))
echo "x+y=$result"

akshrits@CGLX-LPT-159U:~/shell_scripts$ ./command_line_names x=45 y=30
x+y=75


****************Funtion in shell Script(function_example.sh)***************
#! /bin/bash

function F1()
{
	echo "I like bash programming"
}

F1

akshrits@CGLX-LPT-159U:~/shell_scripts$ ./function_example 
I like bash programming


******************functional_parameter.sh*******************
#! /bin/bash

Rectangle_Area()
{
	area=$(($1 * $2))
	echo "Area is : $area"
}

Rectangle_Area 10 20

akshrits@CGLX-LPT-159U:~/shell_scripts$ ./functional_parameter.sh 
Area is : 200


***************function_return.sh****************************
#! /bin/bash

function greeting()
{
	str="Hello, $name"
	echo $str
}

echo "Enter your name"
read name

val=$(greeting)

echo "Return value of the function is $val"


akshrits@CGLX-LPT-159U:~/shell_scripts$ ./function_return.sh
Enter your name
Akrisht
Return value of the function is Hello, Akrisht



*********************Reading from book.txt using inbuilt function(read_file.sh)****************

#! /bin/bash

file='book.txt'

while read line ; do

echo $line
done < $file


*********************A script which will add 2-3 more line in file(append_file.sh)***********************8

#! /bin/bash

echo "Befor appending the file"

cat book.txt

cat book.txt > book_append.txt

echo "9. Aws clound computing" >> book_append.txt

echo "10. Azure Devops using FAAS" >> book_append.txt

echo "After appending the file"

cat book_append.txt 

*****************************check of the file that will create after appending is exits or not (file_exist.sh)****************
#! /bin/bash

filename=$1

if [ -f "$filename" ] ; then
	echo "File exits"
else
	echo "File does not exits"

fi

akshrits@CGLX-LPT-159U:~/shell_scripts$ ./file_exit.sh  book_append.txt
File exits


************wait command(wait_exmaple.sh)**************************
#! /bin/bash

echo "wait command" &
process_id=$!
wait $peocess_id
echo "Exited with status $?"

akshrits@CGLX-LPT-159U:~/shell_scripts$ ./wait_example.sh
wait command
Exited with status 0




====> ps -aef ///==> to see runnig process



*