This document contains code snippets and outputs from several programming assignments. The assignments involve tasks like displaying logged in users, listing connected devices, modifying process priorities, and measuring system memory. Code examples are provided in C, C++, Python, Java, Shell and Perl to demonstrate the various tasks. The outputs confirm that the programs are working as intended by displaying the expected results.

1. Assignment No. 1
Title:-Write a C/C++ script to display all logged in users.
#include<stdio.h>
#include<sys/utsname.h>
#include<utmp.h>
int main(void)
{
structutmp *n;
char *a;
int i;
setutent();
n=getutent();
while(n!=NULL)
{
if(n->ut_type==7)
{
printf("%9s",n->ut_user);
printf("%12s",n->ut_line);
//a=ctime(&n->ut_time);
printf(" ");
for(i=4;i<16;i++)
printf("%c",a[i]);
printf(" (");
printf("%s",n->ut_host);

2. printf(")");
printf("n");
}
n=getutent();
}
}
Output:
[jay@localhost se_b_29]$gccallloggedin.c
[jay@localhost se_b_29]$./a.out
jay :0 ೦^H೦೦H೦೦೦PTI (:0)
jaypts/0 ೦^H೦೦H೦೦೦PTI (:0)
// [Ctrl+Altr+F4] login as jay in tty4

3. Assignment No. 2
Title:-Write a function to display the list of devices connected to your system including the
physical names and its instance number. Write a function using mount and unmount command to
mount device and un-mount it.
# include <dirent.h>
# include <stdio.h>
# include <sys/stat.h>
# include<string.h>
# include<fcntl.h>
void quit(char *,int);
char *path="/run/media/root/";
struct file1
{
char *filename;
} f[50];
int main()
{
DIR *dir;
int i=0,k=0,count=1;
structdirent *direntry;
if ((dir=opendir(path))==NULL)
quit("opendir",1);
printf("n List of connected usb to this computer: n");
while((direntry=readdir(dir)) !=NULL)
{
if(!strcmp(direntry->d_name,".")||!strcmp(direntry->d_name,".."))
{
}
else
{
f[k].filename=direntry->d_name;
printf(" %d. %s n",count,f[k].filename);
k++;
count++;

4. }
i++;
}
closedir(dir);
return 0;
}
Output:
[jay@localhost se_b_29]$gcc conn.cquit.o
[jay@localhost se_b_29]$./a.out
List of connected usb to this computer:
1. SONY_16GM

5. Assignment no 4
Title: C/C++ Program to assign nice values to processes and dynamically monitor them.
#include<stdio.h>
#include<stdlib.h>
#include<sys/resource.h>
#include<unistd.h>
int main()
{
int rc, nc;
int ch;
while(1)
{
system("ps axl");
printf("n Current value can be checked from above table");
printf("n the current priority process is %d is
%d",getpid(),getpriority(PRIO_PROCESS,0));
printf("n Enter new nice value");
scanf("%d",&nc);
rc=setpriority(PRIO_PROCESS,0,nc);
if(0 != rc)
{
perror("setpriority");
}
sleep(2);
printf("n the current priority process is %d is
%d",getpid(),getpriority(PRIO_PROCESS,0));
printf("n do you want to continue(1 continue and 0 for exit):");
scanf("%d",&ch);
if(ch==0)
exit(0);
}
return 0;
}
==================================================================

6. ======================
OutPut:-
0 0 2037 1 20 0 578004 18364 poll_sSl ? 0:00 /usr/libexe
4 0 2040 2037 20 0 8456 668 unix_s S ? 0:00 gnome-pty-h
4 0 2041 2037 20 0 116008 2276 wait Sspts/0 0:00 bash
4 0 2064 2041 20 0 199540 3992 wait S pts/0 0:00 su
4 0 2067 2064 20 0 116012 2316 wait S pts/0 0:00 bash
0 0 2179 1 20 0 665848 17396 poll_sSl ? 0:00 file-roller
1 0 2334 2 20 0 0 0 worker S ? 0:00 [kworker/0:
1 0 2335 2 20 0 0 0 worker S ? 0:00 [kworker/0:
0 0 2355 1461 20 0 320988 11312 pipe_w S ? 0:15 /usr/bin/py
0 0 2371 1461 20 0 320328 10744 pipe_w S ? 0:15 /usr/bin/py
0 0 2373 2067 30 10 4164 324 wait SN+ pts/0 0:00 ./a.out
0 0 2375 1461 20 0 320464 10556 - Rl ? 0:00 /usr/bin/py
0 0 2377 2373 30 10 110700 828 - RN+ pts/0 0:00 psaxl
Current value can be checked from above table
the current priority process is 2373 is 10
Enter new nice value
Title:-C/C++ program to identify the available memory in the system.

7. /*
* C program to print the system statistics like system uptime,
* total RAM space, free RAM space, process count, page size
*/
#include <sys/sysinfo.h> // sysinfo
#include <stdio.h>
#include <unistd.h> // sysconf
#include "syscalls.h" // just contains a wrapper function - error
int main()
{
struct sys infomyinfo;
unsigned long total_bytes;
unsigned long total_fb;
unsigned long total_fc;
if (sysinfo(&myinfo) != 0)
error("sysinfo: error reading system statistics");
total_bytes = myinfo.mem_unit * myinfo.totalram;
total_fb = myinfo.mem_unit * myinfo.freeram;
total_fc = total_bytes - total_fb;
printf("total usable main memory is %lu Bytes, %lu MBn",total_bytes,
total_bytes/1024/1024);
printf("Free available memory is: %lu Bytes, %lu MBn",total_fc, (((total_fb)/1024)/1024));
printf("Uptime: %ld:%ld:%ldn", myinfo.uptime/3600, myinfo.uptime%3600/60, myinfo.uptime%60);
printf("Process count: %dn", myinfo.procs);
printf("Page size: %ld bytesn", sysconf(_SC_PAGESIZE));
return 0;
}

8. Output:-
[jay@localhost se_b_29]$ gccmyram_c.c
[jay@localhost se_b_29]$ ./a.out
total usable main memory is 1036783616 Bytes, 988 MB
// Here is total usable memory
Free available memory is: 962154496 Bytes, 71 MB
// Free available memory
Uptime: 1:3:57
// Time from log in
Process count: 279
//All process count
Page size: 4096 bytes
// Page size
// compare memory output with system-call output
[jay@localhost se_b_47]$ free -m
total used free shared buffers cached
Mem: 988 918 70 0 18 240
// total memory is 988 anf free memory is 70
-/+ buffers/cache: 660 328
Swap: 2079 6 2073

9. package hello;
importjava.io.BufferedReader;
importjava.io.InputStreamReader;
public class Main
{
public static void main(String[] args)
{
int count=0;
try
{
String line;
Process p=Runtime.getRuntime().exec("who");
p.waitFor();
BufferedReader in=new BufferedReader(new InputStreamReader(p.getInputStream()));
while((line=in.readLine()) != null)
{
System.out.println(line);
count++;
}
System.out.print("n Number of users are:"+count);
in.close();
}
catch(Exception err)
{
err.printStackTrace();
}
}
}
/// --- OUTPUT ---///
jay :0 2013-09-23 16:22 (:0)
jay tty3 2013-09-23 16:24
jay tty4 2013-09-23 16:25
Number of users are:3

10. Title:-Java Program to display the list of devices connected to your system including the
physical names and its instance number
import java.io.*;
public class connected
public static void main(String[] args)
{
String path = "/run/media/root/";
File file = new File(path);
String[] myFiles;
int count=1;
if(file.isDirectory())
{
myFiles = file.list();
System.out.println("n List of connected usb to this computer:");
for (int i=0; i<myFiles.length; i++) {
System.out.println("n"+count+". "+myFiles[i]);
count++;
}
System.out.println();
}
}
}
Output:-
[jay@localhost se_b_29]$ java connected
List of connected usb to this computer:
1 SONY_16GM

12. Assignment No 13
Title:-Write python script to display all logged in users.
Import psutil
print("nList of currently logged in users in the system are as
follows:n");
count=1;
for temp in psutil.get_users():
print("nuser:",count);
count=count+1;
print(temp);
print("n Total number of user logged into system:",count-1);
output:
[jay@localhost se_b_47]$ cd /tmp
[jay@localhosttmp]$ python python1.py
List of currently logged in users in the system are as follows:
('nuser:', 1)
user(name='root', terminal=':0', host=':0', started=1379354752.0)
('nuser:', 2)
user(name='root', terminal='pts/0', host=':0', started=1379356032.0)
('nuser:', 3)
user(name='root', terminal='tty4', host='', started=1379355776.0)
('nTotal number of user logged into system:', 3)
[[jay@localhosttmp]$ w
23:56:51 up 20 min, 3 users, load average: 0.30, 0.33, 0.27

13. USER TTY LOGIN@ IDLE JCPU PCPU WHAT
jay :0 23:36 ?xdm? 2:48 0.13s gdm-session-worker [pam/gdm-pas
jaypts/0 23:56 3.00s 0.02s 0.00s w
jay tty4 23:53 ? 0.01s 0.01s -bash
[jay@localhosttmp]$ w
23:57:37 up 21 min, 4 users, load average: 0.13, 0.28, 0.26
USER TTY LOGIN@ IDLE JCPU PCPU WHAT
jay :0 23:36 ?xdm? 2:51 0.13s gdm-session-worker [pam/gdm-pas
jay/0 23:56 1.00s 0.03s 0.01s w
jay tty4 23:53 ? 0.01s 0.01s -bash
jay tty2 23:57 ? 0.02s 0.02s -bash
[jay@localhosttmp]$ w
23:57:58 up 22 min, 3 users, load average: 0.09, 0.26, 0.25
USER TTY LOGIN@ IDLE JCPU PCPU WHAT
jay :0 23:36 ?xdm? 2:54 0.14s gdm-session-worker [pam/gdm-pas
jaypts/0 23:56 6.00s 0.03s 0.00s w
jay tty4 23:53 ? 0.01s 0.01s -bash

14. Assignment no 14
Title:-Python Program to demonstrate debugging of script.
14 B.I) Python program to demonstrate to debugging script.
import sys
importpdb
pdb.set_trace();
print("n Enter the numbers:");
a=input();
b=input();
c=int(a)+int(b);
print("n the first number:");
print(a);
print("n the second number:");
print(b);
print("n The addition of two numbers:");
print(c);
///--- OUTPUT ---///
[jay@localhost se_b_47]$ python debug.py
> /jay/debug.py(4)<module>()
->print("n Enter the numbers:");
(Pdb) n
Enter the numbers:
> /jay/debug.py(5)<module>()
-> a=input();
(Pdb) n
11
> /jay/debug.py(6)<module>()
-> b=input();
(Pdb) n
12
> /jay/debug.py(7)<module>()
-> c=int(a)+int(b);
(Pdb) n
> /jay/debug.py(8)<module>()
->print("n the first number:");
(Pdb) n
the first number:

15. > /jay/debug.py(9)<module>()
->print(a);
(Pdb) n
11
> /jay/debug.py(10)<module>()
->print("n the second number:");
(Pdb) n
the second number:
> /jay/debug.py(11)<module>()
->print(b);
(Pdb) n
12
> /jay/debug.py(12)<module>()
->print("n The addition of two numbers:");
(Pdb) n
The addition of two numbers:
> /jay/debug.py(13)<module>()
->print(c);
(Pdb) n
23

17. Assignment No. 15
Title:-Write a shell program to convert all lowercase letter in a file to uppercase letter.
#!/bin/bash
# get filename
echo -n "Enter File Name : "
readfileName
# make sure file exits for reading
if [ ! -f $fileName ]; then
echo "Filename $fileName does not exists"
exit 1
fi
# convert uppercase to lowercase using tr command
tr '[a-z]' '[A-Z]' < $fileName
Output:
[jay@localhost se_b_29]$cat data.txt
Larry larry@example.com 111-1111
Curly curly@example.com 222-2222
Moe moe@example.com 333-3333
[jay@localhost se_b_29]$ perl 7.sh
Enter File Name : data.txt
LARRY LARRY@EXAMPLE.COM 111-1111
CURLY CURLY@EXAMPLE.COM 222-2222
MOE MOE@EXAMPLE.COM 333-3333

18. Assignment No 17
Title:- Write a Perl program that reads a file and counts the number of lines, characters, and
words it contains and also prints count of the number of times the word appeared
$lines=0;
$words=0;
$chars=0;
print("nnCountingnumbar of words, lines and charactersn");
open(FILE,"<perl.txt");
while(<FILE>)
{
$lines++;
$chars+=length($_);
$words+=scalar(split(/W+/,$_));
}
print("nThenumbar of lines are=$lines");
print("nThe number of words are=$words");
print("nThe number of characters are=$chars");
close FILE;
print("nnWord count of word in the input file");
open(FILE,"<perl.txt");
my %count_of;
while(my $line=<FILE>)
{
foreach my $word(split /s+/,$line)

19. {
$count_of{$word}++;
}
}
print("nWords and their count:nn");
for my $word(sort keys %count_of)
{
print "'$word':$count_of{$word}n";
}close FILE
output :
[jay@localhost se_b_29]$ cd home
[jay@localhost home]$perl perl1.pl
Counting numbar of words, lines and characters
The numbar of lines are=1
The number of words are=4
The number of characters are=22
Word count of word in the input file

20. Words and their count:
'is':1
'program.':1
'test':1
'this':1

22. Group C
Assignment No 1
Title:-Write program to find number of CPU cores and CPU Manufacturer
publicclassNewClass
{
publicstaticvoid main(String[] args)
{
String nameOS = "os.name";
String versionOS = "os.version";
String architectureOs="os.arch";
System.out.println("n The information about processor n no. of CPU in the System
are:-");
System.out.println("Available processors (cores): " +
Runtime.getRuntime().availableProcessors());
System.out.println(System.getenv("NUMBER_OF_PROCESSORS"));
System.out.println("n Processor Manufacturer");
System.out.println(System.getenv("PROCESSOR_IDENTIFIER"));
System.out.println("n n the Information about OS");
System.out.println("n Name of the OS:-"+System.getProperty(nameOS));
System.out.println("n VERSION of the OS:-"+System.getProperty(versionOS));
System.out.println("n Architecture of the OS:-"+System.getProperty(architectureOs));
}
}
///--- OUTPUT ---///
The information about processor
no. of CPU in the System are:-
Available processors (cores): 1
Processor Manufacturer
null
the Information about OS
Name of the OS:-Linux
VERSION of the OS:-3.9.5-301.fc19.x86_64

23. Architecture of the OS:-amd64