UNIX COMMANDS
1) To Display the Date:
[mca0610015@linux ~]$ date
Tue Jan 8 15:20:42 IST 2008
2) To Display the Time:
[mca0610015@linux ~]$ time
real 0m0.000s
user 0m0.001s
sys 0m0.000s
[mca0610015@linux ~]$
3)To Display the calendar:
[mca0610015@linux ~]$ cal
January 2008
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
4) To clear the screen:
[mca0610015@linux ~]$clear
5) To Create a new directory:
[mca0610015@linux sample]$ mkdir first
[mca0610015@linux sample]$
6) To check how many users activated currently:
[mca0610015@linux nana]$ who
mca06100 pts/1 Jan 8 15:21 (192.169.3.20)
mca06100 pts/2 Jan 8 15:17 (192.169.3.10)
mca06100 pts/3 Jan 8 15:27 (192.169.3.33)
mca06100 pts/4 Jan 8 15:18 (192.169.3.36)
mca06100 pts/5 Jan 8 15:18 (192.169.3.18)
mca06100 pts/6 Jan 8 15:19 (192.169.3.43)
7) To Display the current Login:
[mca0610015@linux nana]$ who am i
mca06100 pts/24 Jan 8 15:24 (192.169.3.44)
[mca0610015@linux nana]$
8) To Change the Directory:
[mca0610015@linux ~]$ cd sample
[mca0610015@linux sample]$
9) To Exit to previous directory:
[mca0610015@linux sample]$ cd ..
[mca0610015@linux ~]$
10) To Create a new File:
[mca0610015@linux ~]$ cat > vel
hi i am velmurugan
[mca0610015@linux ~]$
11) Display the content of File:
[mca0610015@linux ~]$ cat vel
hi i am velmurugan
[mca0610015@linux ~]$
12) To Display the Present working directory:
[mca0610015@linux sample]$ pwd
/home/mca0610015/sample
[mca0610015@linux sample]$
13) To Display the Long form of information of files:
[mca0610015@linux ~]$ ls -l
total 32
drwxrwxr-x 2 mca0610015 mca0610015 4096 Jan 8 15:26 kgln
drwxrwxr-x 2 mca0610015 mca0610015 4096 Jan 8 15:29 nana
drwxrwxr-x 3 mca0610015 mca0610015 4096 Jan 8 15:40 sample
-rw-rw-r-- 1 mca0610015 mca0610015 19 Jan 8 15:47 vel
[mca0610015@linux ~]$
14) To Display the Hidden files
[mca0610015@linux ~]$ ls -a
. .bash_history .bash_profile .emacs .kde nana vel .zshrc
.. .bash_logout .bashrc .gtkrc kgln sample .xemacs
[mca0610015@linux ~]$
15) To Copy the file in to another File
[mca0610015@linux ~]$ cp press vel
[mca0610015@linux ~]$ cat vel
hi i am vel
[mca0610015@linux ~]$
16) To Display the Process State
[mca0610015@linux ~]$ ps
PID TTY TIME CMD
9307 pts/24 00:00:00 bash
12257 pts/24 00:00:00 ps
[mca0610015@linux ~]$
17) To Remove the File:
Before Remove:
[mca0610015@linux ~]$ ls -l
total 40
drwxrwxr-x 2 mca0610015 mca0610015 4096 Jan 8 15:26 kgln
drwxrwxr-x 2 mca0610015 mca0610015 4096 Jan 8 15:29 nana
-rw-rw-r-- 1 mca0610015 mca0610015 12 Jan 8 16:11 press
drwxrwxr-x 3 mca0610015 mca0610015 4096 Jan 8 16:05 sample
-rw-rw-r-- 1 mca0610015 mca0610015 12 Jan 8 16:11 vel
[mca0610015@linux ~]$ rm press
After Remove:
[mca0610015@linux ~]$ ls -l
total 32
drwxrwxr-x 2 mca0610015 mca0610015 4096 Jan 8 15:26 kgln
drwxrwxr-x 2 mca0610015 mca0610015 4096 Jan 8 15:29 nana
drwxrwxr-x 3 mca0610015 mca0610015 4096 Jan 8 16:05 sample
-rw-rw-r-- 1 mca0610015 mca0610015 12 Jan 8 16:11 vel
[mca0610015@linux ~]$
18) To Remove the Directory:
Before Remove:
[mca0610015@linux ~]$ ls -l
total 32
drwxrwxr-x 2 mca0610015 mca0610015 4096 Jan 8 15:26 kgln
drwxrwxr-x 2 mca0610015 mca0610015 4096 Jan 8 15:29 nana
drwxrwxr-x 3 mca0610015 mca0610015 4096 Jan 8 16:05 sample
-rw-rw-r-- 1 mca0610015 mca0610015 12 Jan 8 16:11 vel
[mca0610015@linux ~]$ rmdir nana
After Remove:
[mca0610015@linux ~]$ ls -l
total 24
drwxrwxr-x 2 mca0610015 mca0610015 4096 Jan 8 15:26 kgln
drwxrwxr-x 3 mca0610015 mca0610015 4096 Jan 8 16:05 sample
-rw-rw-r-- 1 mca0610015 mca0610015 12 Jan 8 16:11 vel
[mca0610015@linux ~]$
19) To Sort Ascending and descending order:
[mca0610015@linux ~]$ cat > mani
vel
arun
sathish
press
manikandan
venki
bala
Ascending:
nana[mca0610015@linux ~]$ sort mani
arun
bala
manikandan
nana
press
sathish
vel
venki
Desending:
[mca0610015@linux ~]$ sort -r mani
venki
vel
sathish
press
nana
manikandan
bala
arun
[mca0610015@linux ~]$
To Execute the C program:
[mca0610015@linux ~]$ cat sam
main()
{
printf("Welcome");
}
[mca0610015@linux ~]$ cc sam.c
sam.c:5:2: warning: no newline at end of file
[mca0610015@linux ~]$ ./a.out
Welcome[mca0610015@linux ~]$
2. program to create, open, write, Read and Copy.
#include<stdio.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<fcntl.h>
int n,n1,nn,nn1,m,nn2,nn3,nn4;
main()
{
char fname[50];
char oldfile[50];
char newfile[50];
char con[100],con1[100];
do
{
printf("1-Create\n");
printf("2-Write\n");
printf("3-Read\n");
printf("4-Copy\n");
printf("5-MERGE\n");
printf("Enter your choice:\n");
scanf("%d",&m);
switch(m){
case 1: printf("Create New:\n");
printf("Enter the File Name:\n");
scanf("%s",fname);
n=creat(fname,00777);
if(n<0){
printf("ERROR File not Created\n");
}
else
{
printf("Successfully Created\n");
}close(n);
break;
case 2: printf("WRITE\n");
printf("Enter the File Name:\n");
scanf("%s",fname);
n = open(fname,O_WRONLY);
if(n<0)
{ printf("ERROR\n");
}
else
{
printf("Enter the Content:\n");
scanf("%s",con);
n1 = write(n,con,100);
}
close(n);
break;
case 3: printf("READ\n");
printf("Enter the File Name:\n");
scanf("%s",fname);
n=open(fname,O_RDONLY);
n1 = read(n,con,100);
if(n1<0)
{ printf("ERROR\n");
}
else
{
printf("%s",con);
}
close(n);
break;
case 4: printf("\nCOPY");
printf("Enter the New File Name:\n");
scanf("%s",fname);
n = creat(fname,00777);
if(n<0)
{
printf("Error File Not Created\n");
}
else
{
printf("Successfully Created");
}
close(n);
printf("Enter the Old File Name\n");
scanf("%s",oldfile);
n = open(oldfile,O_RDONLY);
n1 = read(n,con,100);
if(n1<0)
{
printf("ERROR");
}
else
{
printf("%s",con);
}
printf("Enter the New File Name\n");
scanf("%s",newfile);
nn = open(newfile,O_WRONLY);
if(nn<0)
{
printf("ERROR");
}
else
{
nn1 = write(nn,con,100);
}
close(n);
close(nn);
break;
case 5: printf("Merge\n");
printf("Enter First File Name:");
scanf("%s",fname);
n = open(fname,O_RDONLY);
n1 = read(n,con,100);
if(n1<0)
{
printf("ERROR...");
}
else
{
printf("%s",con);
}
printf("Enter the Second File:\n");
scanf("%s",oldfile);
nn = open(oldfile,O_RDONLY);
nn1 = read(nn,con1,100);
if(nn1<0)
{
printf("ERROR");
}
else
{
printf("%s",con1);
}
printf("Enter the New File NAME:");
scanf("%s",newfile);
nn2 = creat(newfile,00777);
if(nn2<0)
{
printf("ERROR");
}
else
{
nn3 = write(n,con,100);
nn4 = write(nn1,con1,100);
}
close(n);
close(n1);
close(nn);
close(nn1);
close(nn2);
close(nn3);
close(nn4);
break;
}
}while(m<=5);
}
OUTPUT:
3. Directory.c
#include<stdio.h>
#include<dirent.h>
#include<fcntl.h>
#include<sys/types.h>
main()
{
char d_name[10];
DIR *dp;
struct dirent *dest;
printf("Enter the Directory Name:");
scanf("%s",d_name);
dp=opendir(d_name);
if(dp<0)
{
printf("DIRECTORY DOES NOT EXIST...");
}
else
{
while((dest=readdir(dp))!=NULL)
{
printf("%s",dest->d_name);
}
}
closedir(dp);
}
Output:
[mca0610015@localhost ~]$ cc directory.c
[mca0610015@localhost ~]$ ./a.out
Enter the Directory Name:sample
kar...firstoneba[mca0610015@localhost ~]$
4 . File Types:
#include<stdio.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<fcntl.h>
int main()
{
struct stat *buff;
char fname[20];
int n;
printf("\nEnter File Name:");
scanf("%s",fname);
n=lstat(fname,buff);
if(n<0)
printf("ERROR");
else
{
printf("\n\nFile Type:");
if(S_ISREG(buff->st_mode))
printf("REGULAR FILE");
else if(S_ISDIR(buff->st_mode))
printf("Directory File");
else if(S_ISCHR(buff->st_mode))
printf("Character File");
else if(S_ISBLK(buff->st_mode))
printf("Block File");
else if(S_ISFIFO(buff->st_mode))
printf("Fifo File");
else
printf("No Such File");
}
printf("\n\nFile Size: %d",buff->st_size);
printf("\n\nUSER ID: %d",buff->st_uid);
printf("\n\nGroup ID:%d",buff->st_gid);
return 1;
}
OUTPUT:
[mca0610015@linux ~]$ cc fourth.c
[mca0610015@linux ~]$ ./a.out
Enter File Name:sample
File Type:Directory File
File Size: 4096
USER ID: 583
Group ID:584[mca0610015@linux ~]$
5. SYSTEM DETAILS
#include<stdio.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<sys/utsname.h>
int main()
{
struct utsname name;
int n;
n=uname(&name);
if(n<0)
printf("ERROR");
else
{
printf("\n\nSYSTEM NAME: %s",name.sysname);
printf("\n\nNODE NAME : %s",name.nodename);
printf("\n\nRELEASE : %s",name.release);
printf("\n\nVERSION : %s",name.version);
printf("\n\nMACHINE NAME : %s\n",name.machine);
}
return 1;
}
OUTPUT:
[mca0610015@linux ~]$ ./a.out
SYSTEM NAME: Linux
NODE NAME : linux.example.com
RELEASE : 2.6.9-5.ELsmp
VERSION : #1 SMP Wed Jan 5 19:30:39 EST 2005
MACHINE NAME : i686
[mca0610015@linux ~]$
6. FORK:
#include<stdio.h>
#include<fcntl.h>
#include<sys/stat.h>
#include<sys/types.h>
main()
{
int no,n;
char name[20];
float m1,m2,m3,m4,m5,tot,avg;
printf("\nSTUDENTS DETAILS\n");
printf("\nEnter the No:");
scanf("%d",&no);
printf("\nEnter the Name:");
scanf("%s",name);
printf("Enter Five marks");
scanf("%f%f%f%f%f",&m1,&m2,&m3,&m4,&m5);
n = fork();
printf("%d",n);
if(n==0)
{
tot = m1+m2+m3+m4+m5;
printf("Total Marks is: %f",tot);
avg = tot/5;
printf("Average is :%f",avg);
}
}
OUTPUT:
[mca0610015@linux ~]$ ./a.out
STUDENTS DETAILS
Enter the No:10
Enter the Name:press
Enter Five marks50
50
50
50
50
0Total Marks is: 250.000000Average is :50.0000007388[mca0610015@linux ~]$
7. VFORK:
#include<stdio.h>
#include<fcntl.h>
#include<sys/stat.h>
#include<sys/types.h>
int main()
{
int empno,n;
char empname[50];
float bp,hra,da,pf,net;
printf("\nEnter Employee No:");
scanf("%d",&empno);
printf("\nEnter Employee Name:");
scanf("%s",empname);
printf("\nEnter Basic Pay::");
scanf("%f",&bp);
n =vfork();
if(n==0)
{
printf("Im in Child");
exit(1);
}
else
{
hra = bp*3/100;
da = bp*4/100;
pf = bp*5/100;
net = bp+hra+da-pf;
printf("\nI'm in Parent");
printf("\nHRA :%f",hra);
printf("\nDA :%f",da);
printf("\nPF :%f",pf);
printf("\n-------------*\n");
printf("\nNET PAY : %f",net);
}
}
OUTPUT:
[mca0610015@linux ~]$ ./a.out
Enter Employee No:10
Enter Employee Name:log
Enter Basic Pay::10000
Im in Child
I'm in Parent
HRA :300.000000
DA :400.000000
PF :500.000000
-------------*
NET PAY : 10200.000000
[mca0610015@linux ~]$
8. pipe fork – employee details.
#include<stdio.h>
struct emp{
char name[20];
int id;
float bpay,hra,da,pf,np;
}e;
int main()
{
int fd[2],pid=0,n;
char buf[100];
pipe(fd);
printf("Enter the Employee Name:");
scanf("%s",e.name);
printf("Enter the Employee id:");
scanf("%d",&e.id);
printf("Enter the Basic Pay:");
scanf("%f",&e.bpay);
pid=fork();
if(pid==0)
{
close(fd[1]);
n=read(fd[0],&e,50);
printf("n read =%d",n);
e.hra=e.bpay*.01;
e.da =e.bpay*.02;
e.pf =e.bpay*.03;
e.np =e.bpay+e.hra+e.da-e.pf;
printf("\n\t\t\tEMPLOYEE DETAILS");
printf("\nNAME :%s",e.name);
printf("\nID :%d",e.id);
printf("\nBASIC PAY:%f",e.bpay);
printf("\nHRA :%f",e.hra);
printf("\nDA :%f",e.da);
printf("\nPF :%f",e.pf);
printf("\nNET PAY :%f",e.np);
}
else
{
close(fd[0]);
n=write(fd[1],&e,sizeof(e));
printf("n write =%d",n);
//printf("p=%d",e.name);
}
}
[mca0610044@linux ~]$ cc pipeemp.c
[mca0610044@linux ~]$ ./a.out
Enter the Employee Name:jeni
Enter the Employee id:123
Enter the Basic Pay:1000.
n write =44n read =44
EMPLOYEE DETAILS
NAME :jeni
ID :123
BASIC PAY:1000.000000
HRA :10.000000
DA :20.000000
PF :30.000000
NET PAY :1000.000000[mca0610044@linux ~]$
9. FIFO FILE:
#include<stdio.h>
#include<unistd.h>
#include<string.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<fcntl.h>
#define FIF1 "one.1"
#define FIF2 "two.1"
int main()
{
int fd,fd1,pid,fd3;
char buf[100],buf1[100],fname[100],buf2[100];
mkfifo(FIF1,00777);
mkfifo(FIF2,00777);
pid=fork();
if(pid==0)
{
fd=open(FIF1,O_WRONLY);
printf("Enter the filename");
scanf("%s",&fname);
write(fd,fname,strlen(fname));
close(fd);
fd=open(FIF2,O_RDONLY);
read(fd,buf,100);
printf("%s",buf);
close(fd);
}
else
{
fd1= open(FIF1,O_RDONLY);
read(fd1,buf1,100);
printf("%s",buf1);
close(fd1);
fd3=open(buf1,O_RDONLY);
if(fd3>0)
read(fd3,buf2,100);
else
// strcpy(buf2,"File does not exist");
{
perror("First");
exit(1);
}
close(fd3);
fd1=open(FIF2,O_WRONLY);
write(fd1,buf2,100);
close(fd1);
}
Unlink(FIF1);
Unlink(FIF2);
}
OUTPUT:
[mca0610046@linux ~]$ cc fifofile.c
[mca0610046@linux ~]$ ./a.out
Enter the filename/home/mca0610046/check
hai welcome
/home/mca0610046/checkLinux[mca0610046@linux ~]$
10. server.c
#include<stdio.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<fcntl.h>
#include<sys/ipc.h>
#include<sys/msg.h>
int main()
{
struct msg
{
long type;
char text[10],text1[10];
}m;
int n,n1,ms,mr;
n=msgget((key_t)46,00666|IPC_CREAT);
n1=msgget((key_t)461,00666|IPC_CREAT);
while(1)
{
printf("Enter the text to write in to the queue:");
scanf("%s",m.text);
m.type=100;
// printf("\nqid=%d",n);
ms=msgsnd(n,&m,10,0);
// printf("\nms=%d",ms);
if(ms>=0)
{
// printf("\nMessage is%s=",m.text);
printf("\nmessage send successfully");
}
else
{
printf("\nmessage not send\n");
}
msgrcv(n1,&m,10,0,0);
printf("\n Received :%s",m.text);
}
}
Client.c
#include<stdio.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<fcntl.h>
#include<sys/ipc.h>
#include<sys/msg.h>
int main()
{
struct msg
{
long type;
char text[10];
}m;
int n,mr,ms,n1;
char buf[10];
n=msgget((key_t)46,00666|IPC_CREAT);
n1=msgget((key_t)461,00666|IPC_CREAT);
while(1)
{
// printf("\n%d",n);
mr=msgrcv(n,&m,10,0,0);
printf("\nReceived :%s",m.text);
printf("Enter message:");
scanf("%s",m.text);
m.type=100;
ms=msgsnd(n1,&m,10,0);
printf("n1=%d",n1);
if(ms<0)
{
perror("send..");
exit(1);
}
}
}
