Os Lab Assignment Complete Code Solution

 

GLA University, Mathura
Course: B. Tech (CSE/ IBM related courses) UNIX OS Lab/BCSC 0804
Session: 2020-21

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• Command Implementation On Shell

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1. Implement the following basic commands used in LINUX/ UNIX OS ( Also perform all the commands with their switches as assignment)

ls  - List All Files Present In Current Directory

man - Online Manual(Help) About Command

pwd -  Prints Current Working Directory

who - Lists who is logged on system.

whoami - Lists the Username of the current user logged in

date - Print out Current Date

cal - Print Calender

mkdir - Make a directory

rm - Remove or delete file

rmdir - Remove Directory

cat - Opens an existing file

head - Display first 10 lines of the file

tail - Dispaly last 10 files of the file

more - Look at file

less - Allow Backward movement in the file.

cp - Copy file into directory

mv- Move File

echo - Display the Value

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2. a. Implement the following basic commands used in LINUX/ UNIX OS ( Also perform all the commands with their switches)

cut - Display Only the columns from file

uniq - Filter out the repeated lines in file.

chmod - Change file permissions

du - list the disk usage of the given file.

diff - Check two files are same or not.

history - Lists command You've done recently

last - Find out who has recently log in or out

sort - sorts the content in a file

sed - use to replace text in a file.

grep - find which lines in a file.

pipe - redirect standard output,input or error of one process to another.

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• b. Implement the special shell scripting variables such as $$,$0,$1,$*,$@,$# etc

#!/bin/bash #Implement some Commands $0,$$,$1,$*,$# Etc. echo " File Name : $0" echo "Process Id : $$" echo " First Argument : $1" echo "Second Argument : $2" echo "Third Argument : $3" echo "Quoted values : $@" echo "Quoted values ; $*" echo "Number Of Arguments : $#"

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• SHELL PROGRAMMING

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3. Shell scripts that uses simple commands:

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a. Write a shell script to display current date in a particular format, number of users currently login and current month’s calendar

#!/bin/bash #Display Current Date,Calender and Number of User echo "Current Date :"; date echo "Current Month's of Calender"; cal echo "Number of User :";who -q

b. Write a shell script to display the process name and its process id.

#!/bin/bash #Display Process Name and Process Id echo "Current Process Name: $0" echo "Current Process Id : $$"

c. Write a shell script to take name as a input and display a greeting message to the user by checking system clock. (Ex :- Hello John Good Morning in morning time else Hello John Good Afternoon in afternoon time else Hello John Good Evening in Evening time).

#!/bin/bash #Greeting User by Present Time echo "Enter the Name Of User:" read Name Present_Time=$(date +%H) if [ $Present_Time -lt 12 ] then echo " Good Morning! : $Name " elif [ $Present_Time -gt 12 -a $Present_Time -lt 15 ] then echo " Good AfterNoon! : $Name " elif [ $Present_Time -gt 15 -a $Present_Time -lt 18 ] then echo " Good Evening! : $Name " else echo " Good Night! : $Name " fi

d. Write a shell script to merge the content of 2 files into one file.

#!/bin/bash #concatenate Two Files echo Enter first filename read File1 echo Enter second filename read File2 cat $File1 > third cat $File2 >> third echo After concatination of contents of entered two files echo ---------------------------------------------------- cat third | more echo ----------------------------------------------------

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4. Decision based Shell scripts:

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a. Write a shell script that finds whether an entered number is even or odd.

#!/bin/bash #Check the number is even or odd echo "Enter the Number" read Num test $(($Num % 2)) == 0 && echo "Number is Even" || echo "Number is Odd"

b. Write a shell script to input the name of a file as command line argument and display

whether it is a file, a directory or anything else.

#!/bin/bash #check the argument is file or dir or not if [ -f$1 ] then echo "It is a File" elif [-d$1 ] then echo "It is a directory" else echo "It is not a file or dir" fi

c. Write a shell script to input the marks of a student in 3 subjects and find his grade.

#!/bin/bash #Find Grade Of student in 3 Subject echo "Enter the Marks Of First Subject:" read Mark1 echo "Enter the Marks Of second Subject:" read Mark2 echo "Enter the Marks Of Third Subject:" read Mark3 Total_Mark=$(($Mark1 + $Mark2 + $Mark3)) Avg=$((Total_Mark / 3)) if [ $Avg -ge 60 ] then echo "Grade : First Grade" elif [ $Avg -lt 60 -a $Avg -ge 45 ] then echo "Grade : Second Grade" elif [ $Avg -lt 45 -a $Avg -ge 30 ] then echo "Grade : Third Grade" else echo "Sorry You have No Any Grade!" fi

d. Write a Shell script to accept a filename as argument and displays the last

modification time if the file exists and a suitable message if it doesn't.

#!/bin/bash #print last modification time of file if [ -f$1 ] then echo "Last Modify Time : $(stat -c %y $1)" else echo "it is not a File" fi

e. Write the shell script to take file name as input and if the file exists then print the

number of lines and also print 10th line of that file.

#!/bin/bash #Enter the file as input and if exist print the number of lines and 10th line of that file echo "Enter the file name" read file if [ -f$file ] then l=`cat $file | wc -l` ll=`cat $file | head -10 | tail -1` echo "Number of lines = $l" echo "10th line of file=$ll" else echo "File does not exist" fi

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5. Shell scripts related to loops and arrays

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a. Write a shell script that print multiplication table of a given no.

#!/bin/bash #Print Multiplication Table Of given no by user echo "Enter the Number:" read num echo "Enter the Higher range of number You want to multiply" read Num echo "Multiplication Table" for ((i=1;i<=$Num;i++)) do echo "$num x $i=`expr $num \* $i`" done

b. Write a shell script to implement a timer.

#!/bin/bash #set timer flag=1 while [ $flag -eq 1 ] do echo "Enter a Timer Limit" read t for ((i=$t;i>0;i--)) do echo "Current Time : $(date +%T)" sleep 1 wait done echo "Time Up : $(date +%T)" echo "If You Want new Timer then press 1 for Exit press 0" read flag done

c. Write a shell script that print reverse of a given positive number.

#!/bin/bash #print the Number in reverse order echo "Enter the Number" read Num rem=0 res=0 while [ $Num -gt 0 ] do rem=$(($Num % 10)) res=`expr $res \* 10 + $rem` Num=$(($Num / 10)) done echo "Reverse No. : $res"

d. Write a shell script that print factorial of a given number.

#!/bin/bash #factorial Of Number echo "Enter the Number" read Num res=1 for ((i=$Num;i>0;i--)) do res=`expr $res \* $i` done echo "Factorial of Num : $res"

e. Write a shell to demonstrate the working of array. Input 10 integer in array and

display maximum, minimum, total sum and average of an array.

#!/bin/bash #Array Operations SizeOfArr=10 count=$SizeOfArr i=0 echo "Enter the Array Value" while [ $i -lt $SizeOfArr ] do read arr[$i] i=`expr $i + 1` done max=${arr[0]} min=${arr[0]} sum=0 for i in ${arr[*]} do if [ $i -gt $max ] then max=$i fi if [ $i -lt $min ] then min=$i fi sum=`expr $sum + $i` done avg=`expr $sum / $count` echo "Maximum Value Of Arr : $max" echo "Minimum Value Of Arr : $min" echo "Total Sum Of Value : $sum" echo "Average : $avg" #printf %.2f $(echo "$avg | bc -1) this is not working

f. You are given a file with four space separated columns containing the scores of

students in three subjects. The first column contains a single character (A-Z), the

student identifier. The next three columns have three numbers each. The numbers

are between 0 and 100, both inclusive. These numbers denote the scores of the

students in English, Mathematics, and Science, respectively. Your task is to identify

whether each of the students has passed or failed.

A student is considered to have passed if (s) he has a score 50 or more in each of

the three subjects.

#!/bin/bash #Identify Student is pass or Fail echo "Enter the No. of Student" read num_Std num=$num_Std i=1 count=0 while [ $i -le $num_Std ] do echo "Enter the student$i name only single char" read Std[$i] echo "Enter the Marks(0 - 100) Of English" read eng[$i] echo "Enter the marks(0 - 100) of Math" read Math[$i] echo "Enter the mark(0 - 100) of Science" read Sci[$i] i=`expr $i + 1` done echo "Student Mark's Details" for ((k=1;k<=${#Std[@]};k++)) do echo "Std ${Std[k]}" "Eng ${eng[k]}" "Mat ${Math[k]}" "Sci ${Sci[k]}" done echo "Final Result" for ((j=1;j<=$num;j++)) do if [ ${eng[$j]} -ge 50 ] then count=`expr $count + 1` fi if [ ${Math[$j]} -ge 50 ] then count=`expr $count + 1` fi if [ ${Sci[$j]} -ge 50 ] then count=`expr $count + 1` fi if [ $count == 3 ] then echo "Student $j is Pass in All" else echo "Student $j is Fail" fi count=0 done

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6. Shell scripts related to strings and pipes:

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a. Write a shell script to input two strings from the user and determine whether they are

same or not.

#!/bin/bash #Check the String input by user is same or Not echo "Enter the 1st String" read str1 echo "Enter the 2nd String" read str2 if [ $str1 = $str2 ] then echo "Strings Are Same" else echo "Strings Are Not Same" fi

b. Write a shell script to input a string from the user and determine its length.

#!/bin/bash #find a length of String echo "Enter the String" read str echo "Length Of String : ${#str}"

c. Write a shell script to input two strings from the user and find the occurrences of

string2 in string 1.

#!/bin/bash #find the occurence between two strings echo "Enter the 1st String" read str1 echo "Enter the 2nd String" read str2 grep -o -w "$str2" <<< "$str1" | wc -w

d. Write a shell script to input the name of a file as command line argument and display

the number of characters, words and lines in the file.

#!/bin/bash #Enter a file using command line count word,char &line if [ -f$1 ] then w=`cat $1 | wc -w` c=`cat $1 | wc -c` l=`cat $1 | wc -l` echo "Number of words = $w" echo "Number of Char = $c" echo "Number of lines = $l" else echo "Invalid File" fi

e. Write a shell script to display a list of directories within the current directory and how

much space they consume, sorted from the largest to the smallest.

#!/bin/bash #Print the list of dir and how much space consume in sorted order du -sh */ | sort -nr

f. Write a short script count txt to count the total number of .txt files in the current

directory, and print out this number to screen.

#!/bin/bash #Count txt file in your dir and print number if [ -d$1 ];then echo "Number Of files is $(find "$1" -type f | wc -l)" else echo "Error" fi

e. Write a shell script to create a tsv file containing name, roll no. and age of 10 students. Then use that tsv file to display only the names of the students in alphabetical order.

#!/bin/bash echo "Enter filename" read file echo "Sorted Name of Students" sort $file | awk '{print $1}'

f. You are given a file of tab-delimited weather data (TSV). There is no header
column in this data file. The first five columns of this data are: (a) the name of the
city (b) the average monthly temperature in Jan (in Fahrenheit). (c) The average
monthly temperature in April (in Fahrenheit). (d) The average monthly temperature in
July (in Fahrenheit). (e) the average monthly temperature in October (in
Fahrenheit).You need to sort this file on the basis of average monthly temperature in
April.

#!/bin/bash echo "Enter filename" read file #To get April Column of file sorted sort -k3n $file

• Note:

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