Lab 9.


1: Writing Shell-Scripts
1.Display the Primary and Secondary prompt. Change the primary prompt to your name: temporarily

[ssis9@pace ~]$ echo $PS1
[\u@\h \W]\$
[ssis9@pace ~]$ echo $PS2
>

[ssis9@pace ~]$ PS1="KUNAL#"
KUNAL#





2:  As soon as you login, the prompt should be changed to your name: also the name of the home directory should be automatically displayed.

[ssis9@pace ~]$ PS1="KUNAL#"
KUNAL#




3: Check the content of the Environmental variable SHELL.

KUNAL#echo "$SHELL"

/bin/bash




4: Try the below exercise and check the output.

Note: Type every line and press enter, do not type the entire code in a vi editor.

$continent=”Africa”
$echo “$continent”
 ------------ Africa
$sh
$echo “$continent”
 ------------ No Response
$continent=”Asia”
$echo “$continent”
 ------------ Asia
            $ctrl + d
$echo “$continent”
 ------------ Africa
$sh
$echo “$continent”
 ------------ No Response
            $ctrl + d





5: Try the below exercise and check the output. (Export variables)

Note: Type every line and press enter, do not type the entire code in a vi editor.

$continent=”Africa”
export continent
$echo “$continent”
 ------------ Africa
$sh
$echo “$continent”
 ------------ Africa
$continent=”Asia”
$echo “$continent”
 ------------ Asia
$ctrl + d
$echo “$continent”
 ------------ Africa






6: Write a shell script that takes the user name as input and reports whether he / she has logged in or not.
r=$(who|grep "$1")
if [ -n "$r" ]
then
 echo "$1 logged in"
 echo $r
else
 echo "$1 isn't logged in"
fi



[ssis9@pace ~]$ sh userlog.sh ssis9
ssis9 logged in
ssis9 :0 2017-07-11 23:44 (:0) ssis9 pts/0 2017-07-12 00:54 (:0)
[ssis9@pace ~]$ sh userlog.sh raunak
raunak isn't logged in





7: Write a shell script to display the file name and its contents of all the files that is there in the current directory.

 more * | cat
 




8: Write a shell script, which will take a file name as argument and check whether the file exists and display its access permissions for user.

   file.sh
   if [ -e "$1" ]
   then
     echo "$1 File Found"
   else
     echo "$1 File not found"
   fi





9: Pass three numbers as command line arguments and display the largest number in the given three numbers.


if [ $1 -gt $2 ]; then
    if [ $1 -gt $3 ]; then
        echo "$1 is the largest"
 else
  echo "$3 is the largest"
 fi
elif [ $2 -gt $3 ]; then
 echo "$2 is the largest"
else
 echo "$3 is the largest"
fi





10: Write a shell script which will accept a pattern and a file name. The pattern will be searched in the file provided. Display appropriate messages and perform necessary validations on file.

echo "Enter pattern: "
read pat
echo "Enter filename: "
read filename

if [ -f $filename ]
then
        op=$(grep $pat $filename);
        if [ -n "$op" ]
        then
                echo "$op"
        else
                echo "Pattern not found."
        fi
else


[ssis9@pace ~]$ nano patfile.sh
[ssis9@pace ~]$ sh patfile.sh
Enter pattern:
Char
Enter filename:
friends.txt
7.      Charu Bhandari Goregaon
[ssis9@pace ~]$ sh patfile.sh
Enter pattern:
CCC
Enter filename:
friends.txt
Pattern not found.
[ssis9@pace ~]$ nano patfile.sh
[ssis9@pace ~]$ sh patfile.sh
Enter pattern:
Xhar
Enter filename:
gds
File does not exist
[ssis9@pace ~]$




11: To create a menu program for a) creating a file, b) Creating a  directory, c) copying a file, d) moving a file. (use functions)
a. If the file exists already give the appropriate message
b. If the dir exists already give the appropriate error message
c. Source file should exist if not give a message, It should have read permission if not another message, Destination file either there or not, 
 if not there then create it and copy it. 
 If there, then ask whether to overwrite or not, 
 if yes then overwrite it or else give a message file exists already and not overwritten.

 
 create_file(){
 echo "Enter file name"
 read file
 if [ ! -f $file ]; then
  touch $file
  echo "Successfully created file $file"
 else
  echo "File already exists! Do you want to override the file?(Y/N)"
  read ans
  if [ $ans -eq "Y" -o $ans -eq "y" ]; then
   touch $file
   echo "Successfully created file $file"
  else
   echo "Not creating file $file...";
  fi
 fi
}

create_dir(){
 echo "Enter directory name"
 read dir
 if [ ! -d $dir ]; then
  mkdir $dir
 else
  echo "Directory already exists!"
 fi
}

cp_file(){
 echo "Enter source file name"
 read source
 echo "Enter destination file name"
 read des
 if [ -f $des ]; then
  echo "Files exists at destination! Want to override(Y/N)"
  read ans
  if [ $ans -eq "Y" -o $ans -eq "y" ]; then
   cp $source $des
   echo "Successfully copied $source to $des"
  else
   echo "Not copying file...";
  fi
 else
  cp $source $des
  echo "Successfully copied $source to $des"
 fi
}

mv_file(){
 echo "Enter source file name"
 read source
 echo "Enter destination file name"
 read des
 if [ -f $source ]; then
  if [ -f $des ]; then
   echo "Files exists at destination! Want to override(Y/N)"
   read ans
   if [ $ans -eq "Y" -o $ans -eq "y" ]; then
    mv $source $des
    echo "Successfully moved $source to $des"
   else
    echo "Not moving file...";
   fi
  else
   mv $source $des
   echo "Successfully moved $source to $des"
  fi
 else
  echo "Source file does not exists"
 fi
}
echo "Menu"
echo "1. Create a file"
echo "2. Create a directory"
echo "3. Copy file"
echo "4. Move file"
echo "5. Exit"
read choice
case $choice in
1)create_file;;
2)create_dir;;
3)cp_file;;
4)mv_file;;
5)exit;;
esac





12: Write a function yesno() to display question to user and accept answer as y/n. If answer to the question is y the function should return 0 otherwise 1.
      Use yesno functions for asking different questions. Question will be passed as   parameter to the function.
       Accept filename from user check whether it is file or directory. Use yesno() function to display question do you really want to delete file? If the ans is y, then delete the file or directory.
    
yesno(){
        echo "Do you really want to delete this file? [y/n]"
        read choice
        if [ $choice != 'y' ]
        then
                return 0
        else
                rm $1
                return 1
        fi
}


echo "Enter filename to delete: "
read filename
yesno $filename
ret=$?
if [ $ret -eq 1 ]
then
        echo "$filename deleted"
else
        echo "$filename was not deleted"
fi



[ssis9@pace ~]$ touch hello.ycyc
[ssis9@pace ~]$ sh yesno.sh
Enter filename to delete:
hello.ycyc
Do you really want to delete this file? [y/n]
n
hello.ycyc was not deleted
[ssis9@pace ~]$ sh yesno.sh
Enter filename to delete:
hello.ycyc
Do you really want to delete this file? [y/n]
y
hello.ycyc deleted






13: Write a shell script to store names of four employees and check whether those employees are currently logged in or not. Display appropriate message.
r1=$(who|grep "$1")
if [ -n "$r1" ]
then
 echo "$1 logged in"
 echo $r1
else
 echo "$1 isn't logged in"
fi

r2=$(who|grep "$2")
if [ -n "$r2" ]
then
 echo "$2 logged in"
 echo $r2
else
 echo "$2 isn't logged in"
fi

r3=$(who|grep "$3")
if [ -n "$r3" ]
then
 echo "$3 logged in"
 echo $r3
else
 echo "$3 isn't logged in"
fi

r4=$(who|grep "$4")
if [ -n "$r4" ]
then
 echo "$4 logged in"
 echo $r4
else
 echo "$4 isn't logged in"
fi



[ssis9@pace ~]$ sh userlog.sh raunak ssis9 ssis9 raunak
raunak isn't logged in
ssis9 logged in
ssis9 :0 2017-07-11 23:44 (:0) ssis9 pts/0 2017-07-12 00:54 (:0)
ssis9 logged in
ssis9 :0 2017-07-11 23:44 (:0) ssis9 pts/0 2017-07-12 00:54 (:0)
raunak isn't logged in





14: Accept the users first and last name and the echo the entire name along with some suitable comment.
  
  #fl.sh
  echo "Enter first name"
  read fname
  echo "Enter last name"
  read lname
  echo "Your name is$fname $lname"





15: List all files that have been modified today.

 find . -mtime -1 -print

 




16: Display long listing of only the regular files in the current directory.

  ls -p -l | grep -v /






17: Display details of all files in the 2 “paths” accepted from user. The display should be screen by screen.

  echo "Enter First Path"
  read path1
  echo "Enter Second Path"
  read path2

  echo "-----------Path 1 Files-----------------------"
  ls $path1
  echo "-----------Path 2 Files-----------------------"
  ls $path2





18: Let the script display its name and its PID.

 echo "The script name is $0"
 echo "The script pid is $$"






19: Get the concatenated o/p of 2 files into a third file: Take 3 command line arguments: The first argument is the name of a destination file, 
 and the other two arguments are names of files whose contents are to be placed in the destination file.
 
cat "$2 $3 > $1"





Stretched Assignments:

20: Write a menu driven shell program to:
a.   Display calendar of current month
b. Search for a pattern in all the files/subdirectories from current directory.  
c. Count the no. of directories / sub directories in current directory


ch='y'
while [ $ch == "y" ]
do
echo "1. Calendar of the current month"
echo "2. Search for a pattern"
echo "3. Count no. of directories/ sub-directories in directory"
echo "Enter 1, 2 or 3:"
read choice

case $choice in
        1)      echo "Calendar for this month"
                cal;;
        2)      echo "Enter pattern:"
                read pat
                grep $pat * -r;;
        3)      echo "Here is count of all the directories / sub-directories:"
                ls -r * | wc -l;;
        *)      echo "Enter valid choic.";;
esac




[ssis9@pace ~]$ sh menucal.sh
1. Calendar of the current month
2. Search for a pattern
3. Count no. of directories/ sub-directories in directory
Enter 1, 2 or 3:
1
Calendar for this month
     July 2017
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 31
Do you want to continue?[y/n]
y
1. Calendar of the current month
2. Search for a pattern
3. Count no. of directories/ sub-directories in directory
Enter 1, 2 or 3:
2
Enter pattern:
Virag
friends.txt:2.  Virag Shah Mulund
myfiles/friends.txt:2.  Virag Shah Mulund
myfiles/myfriends.txt:1.        Virag Shah Mulund
myfriends.txt:2.        Virag Shah Mulund
result:2.       Virag Shah Mulund
result:2.       Virag Shah Mulund
Do you want to continue?[y/n]
y
1. Calendar of the current month
2. Search for a pattern
3. Count no. of directories/ sub-directories in directory
Enter 1, 2 or 3:
3
Here is count of all the directories / sub-directories:
60
Do you want to continue?[y/n]
n








21: Display day of week for a given date. (ddmmyyyy) 
           If day is Monday, display message  “Monday Blues”
                         Friday display message “yeh! It’s week end.”
           Similarly display different messages for each day of the week. 


     
echo "Enter date: (dd-mm-yyyy)"
read date
DAY=$(cut -d"-" -f1<<<"$date")
MONTH=$(cut -d"-" -f2<<<"$date")
YEAR=$(cut -d"-" -f3<<<"$date")
newdate="$MONTH/$DAY/$YEAR"

day=$(date -d $newdate +'%A')
#echo $day
case $day in
        "Monday") echo "Monday Blues" ;;
        "Tuesday") echo "Still tuesday" ;;
        "Wednesday") echo "Boring wednesday" ;;
        "Thursday") echo "Nearing weekend" ;;
        "Friday") echo "It's the weekend!" ;;
        "Saturday") echo "One more day off!" ;;
        "Sunday") echo "Monday tomorrow" ;;
        *) echo "Bye" ;;
esac



[ssis9@pace ~]$ nano daydate.sh
[ssis9@pace ~]$ sh daydate.sh
Enter date: (dd-mm-yyyy)
18-12-1995
Monday Blues







22: Display the contents of all .lst files in the current directory.


[ssis9@pace ~]$ cat > abc.lst
hello
lst
file[ssis9@pace ~]$ cat abc.lst
hello
lst
file[ssis9@pace ~]$ cat > def.lst
another
lst
file
[ssis9@pace ~]$ cat def.lst
another
lst
file
[ssis9@pace ~]$ cat *.lst
hello
lst
fileanother
lst
file






23: Design a simple calculator, which will add/subtract/multiply/divide 2 numbers.
eg.   cal 10 20 +   will give o/p as 30.


if [ "$3" == "+" ]
then
 echo $(($2+$1))
elif [ "$3" == "-" ]
then
 echo $(($1-$2))
elif [ "$3" == "*" ]
then
 echo $(($1*$2))
elif [ "$3" == "/" ]
then
 echo $(($1/$2))
else
 echo "Enter proper input."
fi


[ssis9@pace ~]$ sh cal.sh 3 4 -
-1
[ssis9@pace ~]$ sh cal.sh 3 4 /
0
[ssis9@pace ~]$ sh cal.sh 3 4 *
Enter proper input.
[ssis9@pace ~]$ sh cal.sh 3 4 "*"
12
[ssis9@pace ~]$ sh cal.sh 3 4 +
7





24: For a student file with the following fields, rollno, name, marks, Generate 2 files ‘Pass’ and ‘Fail’ containing records of student who have passed or failed. Also count the number of students who have passed or failed.


[ssis9@pace ~]$ cat student
1 Kunal 74
2 Nirbhay 87
3 Shubham 77
4 Shyam 78
5 Babu 43
6 Raj 49
7 Baburaj 46

[ssis9@pace ~]$ cat marks.sh
file="student"
while IFS= read -r line
do
 mark=$(echo "$line" | awk '{print $3}')
 if [ $mark -gt 60 ]
 then
  echo "$line PASS"| awk '{print $1, $2, $3, $4}' >> pass.txt
 else
  echo "$line FAIL"| awk '{print $1, $2, $3, $4}' >> fail.txt
 fi
done < $file

echo "PASS: "$(wc -l < pass.txt)
echo "FAIL: "$(wc -l < fail.txt)


[ssis9@pace ~]$ sh marks.sh 
PASS: 4
FAIL: 3
[ssis9@pace ~]$ cat pass.txt 
1 Kunal 74 PASS
2 Nirbhay 87 PASS
3 Shubham 77 PASS
4 Shyam 78 PASS
[ssis9@pace ~]$ cat fail.txt
5 Babu 43 FAIL
6 Raj 49 FAIL
7 Baburaj 46 FAIL






25: Accept a date string from terminal and display employees born after the input date.


file="emp.lst"
echo "Enter date [mm/dd/yyyy]:"
read newdate
day=$(date -d $newdate +%Y%m%d)
while IFS= read -r line
do
        line2=$( echo "$line" | awk '{split($0,a,"|");print a[5]}' )
        #echo "$line2"
        todate=$(date -d $line2 +%Y%m%d)
        #echo $todate
        if [ $day -gt $todate ]
        then
                echo $line
        fi
done < $file


[ssis9@pace ~]$ sh empdate.sh
Enter date [mm/dd/yyyy]:
08/06/1981
7369|SMITH|CLERK|20|12/17/1980|800
7499|ALLEN|SALESMAN|30|02/20/1981|1600
7521|WARD|SALESMAN|30|02/22/1981|1250
7566|JONES|MANAGER|20|02/04/1981|2975
7698|BLAKE|MANAGER|30|01/05/1981|2850