final os lab print

7/31/2019 Final OS Lab Print

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1 ) Write a shell script that accepts a file name, starting and ending line numbers as arguments

and display all the lines between the given line numbers.

echo "enter file name"read fecho 'enter starting position'

read stecho 'enter ending position'read endecho 'The lines between' $st 'and' $end 'from' $fif [ $st -lt $end ]thenn1=èxpr $st + 1`n2=èxpr $end - 1`sed -n "$n1,$n2 p" $felif [ $st -gt $end ]thenn3=èxpr $st - 1`

n4=èxpr $end + 1`sed -n "$n4,$n3 p" $ffi

Output:

$ sh first.shenter file namefnameenter starting position1enter ending position

4The lines between 1 and 4 from fnamehello worldhello sri

2) Write a shell script that deletes all lines containing a specified word in one or more filessupplied as arguments to it.

echo 'enter a word to be deleted'read wordecho 'enter file name'read fname

echo 'lines in' $fname 'after deleting the word' $word ':'sed "/$word/d" $fname

Output:

$ sh del.shenter a word to be deletedhello


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enter file namesample.shlines in sample.sh after deleting the word hello :hi.....end of the text.....[s11031d0519@www os]$ vi sample.sh

hi.....hello worldhello sit...hello user...end of the text.....

3) Write a shell script that displays a list of all the files in the current directory to which the

user has read, write and execute permissions.

for i in *do

if [ -r $i -a -w $i -a -x $i ]thenecho $ifidone

Output:

$ sh rwper.sha.outfnamelist.sh

newshell.

4)Write a shell script that receives any number of file names as arguments checks if everyargument supplied is a file or directory and reports accordingly. whenever the argument is a

file, the number of lines on it is also reported.

for fname in $*doif [ -f $fname ]thenecho $fname 'is a file'echo 'no.of lines in' $fname ':'

wc -l $fnameelif [ -d $fname ]thenecho $fname 'is a directory'elseecho 'Does not exist'fidone


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Output:

$ sh filedir.sh fnamefname is a fileno.of lines in fname :

5 fname

$ sh filedir.sh fname a.out shellfname is a fileno.of lines in fname :

5 fnamea.out is a fileno.of lines in a.out :

14 a.outshell is a directory

5) Write a shell script that accepts a file names as its arguments, counts and reports the

occurrence of each word that is present in the file argument file in other argument files.

if [ $# -eq 0 ]thenecho "no arguments"elsetr " " "\n" < $1 > tempshiftfor i in $*dotr " " "\n" < $i > temp1y=`wc -l < temp`j=1while [ $j -le $y ]

dox=`head -n $j temp | tail -1`c=`grep -c "$x" temp1`echo $x $cj=`expr $j + 1`donedonefi

Output:

$ sh 5.sh fname sample.sh

hello.... 0hello 3world 1hello 3sri 0end 1of 1the 1text 1


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hdgs 0krfplqw 0

6) Write a shell script to all of the directory files in a directory.

enter a directory nameecho 'enter a directory name'read dnameecho 'The list of directory files in the directory' $dname 'are'cd $dnamels -l | grep '^d'

Output:

$ sh list.sh

os

The list of directory files in the directory os are

list.sh: cd: os: No such file or directorydrwxr-xr-x 3 s11031d0 cs11 4096 Mar 22 11:04 newdrwxr-xr-x 3 s11031d0 cs11 4096 Mar 22 11:07 shell

7)Write a shell script to find factorial of a given number.

echo 'enter a number'read ni=1fact=1

while [ $i -le $n ]dofact=èxpr $fact \* $iì=èxpr $i + 1`doneecho 'The factorial of' $n 'is' $fact

Output:

$ sh fact.shenter a number5

The factorial of 5 is 120

8)Write a awk script to count the number of lines in a file that do not contain vowels.

echo 'enter a file name'read fnawk '$0 !~/[aeiou]/ { c=c+1 }

END { print("The no.of lines that do not contain vowels:",c) }' $fn


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Output:

$ sh lcount.awkenter a file namefnameThe no.of lines that do not contain vowels: 1

9) Write a awk script to find the number of characters,words and lines in a file.

echo "enter a file name"read fnawk '{ w=w+NF

c=c+length($0)}END { print("No.of lines:",NR)

print("No.of words:",w)print("No.of characters:",c)

}' $fn

Output:

$ sh cwlcount.awkenter a file namesample.shNo.of lines: 5No.of words: 11No.of characters: 63

10) Write a C program that makes a copy of a file using standard I/O and system calls.

#include#include

#define MAX_SIZE 1000

main()

{ int fd1,fd2,r1,w1;

char buffer[MAX_SIZE];

char sourceName[100],destName[100];

printf("enter the source file\n");

scanf("%s",sourceName);

printf("enter a new file name");

scanf("%s",destName);

fd1=open(sourceName,O_RDONLY);


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r1=read(fd1,buffer,MAX_SIZE);

fd2=open(destName,O_CREAT|O_RDWR,0600);

w1=write(fd2,buffer,r1);

}

Output:

$ cc 10.c

$ ./a.out

enter the source file

fnameenter a new file namenewfile$ vi fname $vi newfilehello.... hello....x

hello world hello worldhello sit hello sitend of the text end of the text

11)Implement in C the following Unix commands using system calls.

a) cat command#include#define MAX_SIZE 500main(){

int fd1,n;

char buf[MAX_SIZE],fname[20];printf("enter a file name\n");scanf("%s",fname);fd1=open(fname,O_RDONLY);if(fd1==-1)

printf("the file does not exist");else{printf("The contents of file %s are:\n",fname);n=read(fd1,buf,MAX_SIZE);write(1,buf,n);}

}

Output:

$ cc CatCommand11a.c$ ./a.outenter a file namesample.shThe contents of file sample.sh are:


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hi.....hello worldhello sit...hello user...end of the text.....

11b)mv command

#include#includemain(int argc,char *argv[]){

open(argv[1],O_RDONLY);creat(argv[2],S_IWUSR);rename(argv[1],argv[2]);unlink(argv[1]);

}

Output:

$ cc MvPgm11b.c$ ./a.out sample.sh sample$ cat sample.shcat: sample.sh: No such file or directory$ cat samplehi.....hello worldhello sit...hello user...

end of the text.....

12) Write a C program to list directory files in directory.

#include#include#include#includemain(){

struct stat buf;struct dirent *direntp;

DIR *dirp;char dirName[40],name[40];printf("enter directory name\n");scanf("%s",&dirName);dirp=opendir(dirName);while((direntp=readdir(dirp))!=NULL){

stat(direntp->d_name,&buf);


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if(S_ISDIR(buf.st_mode))printf("%s\n",direntp->d_name);

}}

Output:

$ cc ListOfDirFiles12.c$ ./a.outenter directory namenew...new1sri

13) Write a C program to emulate the unix ls l command.

#include#include#include#include#include#include#include#include#include

int main()

{char* getuser(int uid,char* s);char* getperms(int mode,char* s);char* getgroup(int gid,char* s);int cscmp(const void *a, const void *b);struct dirent *d;struct stat st;struct tm *tm;DIR *p;int i=0,j=0,bcount=0;char datestring[17],pstring[10],ustring[20],gstring[20];char cwd[1024];

char *fnames[1024];

getcwd(cwd,sizeof(cwd));p=opendir(cwd);

while(d=readdir(p)){if(d->d_name[0]!= '.'){


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lstat(d->d_name,&st);fnames[i++]=d->d_name;bcount=bcount+st.st_blocks/2;}}

qsort(fnames,i,4,cscmp);

printf("total %d\n",bcount);while(j


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*s++ = other & S_IXOTH ? 'x' : '-';*s = '\0';return s;

}

char* getuser(int uid,char* s)

{struct passwd *pwd;if ((pwd = getpwuid(uid)) != NULL)

strcpy(s,pwd->pw_name);else

snprintf(s,20,"%d",uid);return s;

}

char* getgroup(int gid,char* s){struct group *grp;

if ((grp = getgrgid(gid)) != NULL)strcpy(s,grp->gr_name);

elsesnprintf(s,20,"%d",gid);

return s;}

int cscmp(const void *a, const void *b){const char **ia = (const char **)a;const char **ib = (const char **)b;return strcasecmp(*ia, *ib);

}

Output:

$cc 13.c$./a.outtotal 20-rwxr-xr-x 1 user group 7756 2012-05-02 19:57 a.out-rw-r--r-- 1 user group 2605 2012-05-02 19:56 13.c-rw-r--r-- 1 user group 284 2012-05-01 11:03 A.c-rw-r--r-- 1 user group 275 2012-05-01 11:03 B.c

14) Write a C program to list for every file in a directory, its inode number in a given directory

#include#include#include#includemain(){

struct stat buf;


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struct dirent *direntp;DIR *dirp;char dirName[40],name[40];printf("enter directory name\n");scanf("%s",&dirName);chdir(dirName);

dirp=opendir(dirName);while((direntp=readdir(dirp))!=NULL){

stat(direntp->d_name,&buf);printf("%d %s",buf.st_ino,direntp->d_name);printf("\n");

}}

Output:

$ cc 14.c$ ./a.outEnter Directory Namenew10748078 .11813612 ..11813612 new111813612 sri11813612 core.9696

15) Write a C program that redirects standard output to a file.

#include#includemain(int argc,char **argv){

int fd;if(argc!=3){

printf("please provide necessary arguments");exit(1);

}fd=open(argv[2],O_WRONLY|O_CREAT|O_TRUNC);

if(fd==-1){printf("failed to open a file");exit(1);

}dup2(fd,1);execlp(argv[1],argv[1],NULL);

}


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Output:

$ cc redirect15.c$ ./a.out pwd f1$ cat f1/home/os

16) Write a C program to create a child process and allow the parent to display parent and

the child to display child on the screen.

#include

#includemain(){

pid_t pid;pid=fork();if(pid==-1)

printf("failed to fork");

else if(pid==0)printf("child process:%d\n",getpid());

elseprintf("parent process:%d",getpid());

}

Output:

$ ./a.out

parent process:10210$ child process:10211

$ ./a.out

parent process:10222

$ child process:10223

17) Write a C program to create a Zombie process

#includemain(){

int pid;pid=fork();if(0==pid){

printf("child process %d \n",getpid());_exit(0);

}


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else{

wait(0);sleep(10);printf("parent process \n");

}

}

Output:

$ cc ZombieProcess.c$ ./a.outchild process 10365(Note:After 10 sec Child Process is killed,parent process is continuing,,.)

parent process

18) Write a C program that illustrates how an orphan is created.

i) Orphan process#includemain(){

int pid;pid=fork();if(pid==0){

printf("I am the child process with PID:%d and my parent idis:%d\n\n",getpid(),getppid());

sleep(15);

printf("I am the child process with PID:%d and my parent idis:%d\n",getpid(),getppid());}

else{

printf("I am the parent process with PID:%d\n \n",getpid());printf("My child's PID is:%d\n\n",pid);sleep(1);

}printf("PID %d terminates \n",getpid()); /*Both processes execute this*/}

Output:

$ cc orphan18.c

$ ./a.out

I am the parent process with PID:10503My child's PID is:10504I am the child process with PID:10504 and my parent id is:10503


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PID 10503 terminates$ I am the child process with PID:10504 and my parent id is:1PID 10504 terminates

19) Write a C program that illustrates how to executing two commands concurrently with a

command pipe.

#includemain(int argc,char **argv){

int pid,fd[2],p;if(argc!=3){

printf("insufficient arguments");exit(1);

}p=pipe(fd);

if(p==-1){

printf("pipe creation failed");exit(1);

}pid=fork();if(pid==-1){

printf("fork failed");exit(1);

}if(pid==0)

{ close(fd[0]);dup2(fd[1],1);close(fd[1]);execlp(argv[1],argv[1],NULL);

}else{

close(fd[1]);dup2(fd[0],0);close(fd[0]);execlp(argv[2],argv[2],NULL);

}}

Output:

$ cc pipetwocommandsexec19.c

$ ./a.out

insufficient arguments.


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$ ./a.out cat|sort sample

end of the text.....

hello sit...

hello user...

hello world

hi.....

20) Write a C program that illustrates communication between two unrelated process using

named pipe.

Program1:#include#includemain(){

char *msg="hai";int fd,pfd;pfd=mkfifo("pipe1",0666);if(pfd==-1){

printf("error creating the named pipe");exit(1);

}fd=open("pipe1",O_WRONLY);if(fd==-1){

printf("failed to open a pipe");

exit(1);}write(fd,msg,4);unlink("pipe1");

}Program2:

#include

#includemain()

{char msg[10];int fd,n;fd=open("pipe1",O_RDONLY);if(fd==-1){

printf("failed to open pipe");exit(1);

}


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n=read(fd,msg,10);printf("message: %s\n",msg);

}Output:

$ cc 20a.c -o a

$ cc 20b.c -o b

$ ./a &

[1] 5862

$ ./b

message: hai

21)write a C program in which a parent writes a message to a pipe and the child reads the

message.

#includemain(){

int p[2],pid;char *buf;buf=(char *) malloc(10);pipe(p);pid=fork();if(pid>0){printf("parent is writing on pipe\n");

write(p[1],"hello",5); }else {

read(p[0],buf,5);printf("child is reading %s \n",buf);}

close(p[0]);close(p[1]); }

Output:

$ cc ReadWritePipe21.c

$ ./a.out

parent is writing on pipe

$ child is reading hello.

22)Write C program to transfer large amount of data between processes using

a)Pipe:#include#includemain()

{int p[2],pid,i,j;


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char *buf,s[30],*src="10";buf=malloc(30);pipe(p);pid=fork();srand(47);for(i=0;i0){

for (j = 0; j < 30; j++){

s[j] = src[rand()%2];}

printf("Writing data to pipe : %s\n",s);write(p[1],s,30);

}else{

read(p[0],buf,30);printf("Recieving data from pipe : %s \n\n",buf);

}sleep(1);}close(p[0]);close(p[1]);

}Output:

$cc 21a.c

$./a.outWriting data to pipe : 100011110000100001111011001011Recieving data from pipe : 100011110000100001111011001011

b)FIFO:#include#includemain()

{int pid,i,j,fd;char *buf,s[30],*src="10";buf=malloc(30);

fd=mkfifo("myfifo",0666);pid=fork();srand(57);for(i=0;i0){

for (j = 0; j < 30; j++){


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fd=open("myfifo",O_WRONLY);printf("Writing data to FIFO : %s\n",s);write(fd,s,30);

}else{

fd=open("myfifo",O_RDONLY);read(fd,buf,30);printf("Recieving data from FIFO : %s \n\n",buf);

}sleep(1);}unlink("myfifo");

}

Output:

$cc 21b.c$./a.outWriting data to FIFO : 101101110101010111000000100110Recieving data from FIFO : 101101110101010111000000100110

c)Message queue:

#include

#include#include#include

main(){

int pid,i,j,msqid;char *buf,s[30],*src="10";buf=malloc(30);msqid=msgget((key_t)7,IPC_CREAT|0666);pid=fork();srand(67);

for(i=0;i0){

for (j = 0; j < 30; j++){


printf("Writing data to message queue : %s\n",s);


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msgsnd(msqid,&s,30,0);

}else{ msgrcv(msqid,buf,30,0,0);

printf("Recieving data from message queue : %s \n\n",buf);

}sleep(1);}

}

Output:

$cc 21c.c$./a.outWriting data to message queue : 000001010000001100100111011111Recieving data from message queue : 000001010000001100100111011111

23)Write a C program that implements a producer-consumer system with two process(using

semaphores).

#include#include#include#include#includevoid abc(){

printf("bye bye from child\n");

exit(0);}void xyz(){

printf("bye bye from parent\n");exit(0);

}main(){

int semid;int pid;struct sembuf sop;

semid=semget((key_t)29,1,IPC_CREAT|0666);if(-1==semid){

perror("semget:");exit(1);

}semctl(semid,0,SETVAL,6);printf("semid=%d\n",semid);pid=fork();


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if(0==pid){

sop.sem_num=0;sop.sem_op=-1;sop.sem_flg=0;signal(SIGALRM,abc);

alarm(6);while(1){

semop(semid,&sop,1);printf("child%d\n",semctl(semid,0,GETVAL,0));sleep(1);

}}else{ sleep(7);

sop.sem_num=0;sop.sem_op=1;

sop.sem_flg=0;signal(SIGALRM,xyz);alarm(6);while(1){

semop(semid,&sop,1);printf("parent%d\n",semctl(semid,0,GETVAL,0));sleep(1);}}}

Output:

$ cc 27.c

$ ./a.outsemid=327684child5child4child3child2child1child0bye bye from childparent1parent2parent3

parent4parent5parent6bye bye from parent

24)Write client and server programs(using c) for interaction between server and client

processes using Unix Domain Sockets.


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a)unix domain sockets(interaction between server and client)(server)#include #include #include #include

#define NSTRS 3 /* no. of strings */#define ADDRESS "mysocket" /* addr to connect */

/** Strings we send to the client.*/

char *strs[NSTRS] = {"This is the first string from the server.\n","This is the second string from the server.\n","This is the third string from the server.\n"

};

main(){

char c;FILE *fp;int fromlen;register int i, s, ns, len;struct sockaddr_un saun, fsaun;

/** Get a socket to work with. This socket will* be in the UNIX domain, and will be a* stream socket.

*/if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {

perror("server: socket");exit(1);

}

/** Create the address we will be binding to.*/saun.sun_family = AF_UNIX;strcpy(saun.sun_path, ADDRESS);

/** Try to bind the address to the socket. We* unlink the name first so that the bind won't* fail.** The third argument indicates the "length" of* the structure, not just the length of the* socket name.*/


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unlink(ADDRESS);len = sizeof(saun.sun_family) + strlen(saun.sun_path);

if (bind(s, &saun, len) < 0) {perror("server: bind");exit(1);

}

/** Listen on the socket.*/if (listen(s, 5) < 0) {

perror("server: listen");exit(1);

}

/** Accept connections. When we accept one, ns

* will be connected to the client. fsaun will* contain the address of the client.*/if ((ns = accept(s, &fsaun, &fromlen)) < 0) {

perror("server: accept");exit(1);

}

/** We'll use stdio for reading the socket.*/fp = fdopen(ns, "r");

/** First we send some strings to the client.*/for (i = 0; i < NSTRS; i++)

send(ns, strs[i], strlen(strs[i]), 0);

/** Then we read some strings from the client and* print them out.*/for (i = 0; i < NSTRS; i++) {

while ((c = fgetc(fp)) != EOF) {putchar(c);

if (c == '\n')break;

}}

/*


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* We can simply use close() to terminate the* connection, since we're done with both sides.*/close(s);

exit(0);

}

Output:

$ cc sockserver28a.c$ ./a.outThis is the first string from the client.This is the second string from the client.This is the third string from the client.

Client.c#include

#include #include #include

#define NSTRS 3 /* no. of strings */#define ADDRESS "mysocket" /* addr to connect */

/** Strings we send to the server.*/

char *strs[NSTRS] = {"This is the first string from the client.\n",

"This is the second string from the client.\n","This is the third string from the client.\n"

};

main(){

char c;FILE *fp;register int i, s, len;struct sockaddr_un saun;

/*

* Get a socket to work with. This socket will* be in the UNIX domain, and will be a* stream socket.*/if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {

perror("client: socket");exit(1);

}


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/** Create the address we will be connecting to.*/saun.sun_family = AF_UNIX;strcpy(saun.sun_path, ADDRESS);

/** Try to connect to the address. For this to* succeed, the server must already have bound* this address, and must have issued a listen()* request.** The third argument indicates the "length" of* the structure, not just the length of the* socket name.*/len = sizeof(saun.sun_family) + strlen(saun.sun_path);

if (connect(s, &saun, len) < 0) {perror("client: connect");exit(1);

}

/** We'll use stdio for reading* the socket.*/fp = fdopen(s, "r");

/*

* First we read some strings from the server* and print them out.*/for (i = 0; i < NSTRS; i++) {

while ((c = fgetc(fp)) != EOF) {putchar(c);

if (c == '\n')break;

}}

/** Now we send some strings to the server.*/for (i = 0; i < NSTRS; i++)

send(s, strs[i], strlen(strs[i]), 0);

/** We can simply use close() to terminate the* connection, since we're done with both sides.


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*/close(s);

exit(0);}

Output:

$ cc sockserver28b.c$ ./a.outThis is the first string from the server.This is the second string from the server.This is the third string from the server.

25)Write a C program that illustrates two process communicating via shared memory.

a)shared memory(client)#include

#include #include #include #define SHMSZ 27main(){

char c;int shmid;key_t key;char *shm, *s;key = 5678;if ((shmid = shmget(key, SHMSZ, IPC_CREAT | 0666)) < 0) {

perror("shmget");exit(1);

}printf("shmid=%d\n",shmid);

/** Now we attach the segment to our data space.*/if ((shm = shmat(shmid, NULL, 0)) == (char *) -1) {

perror("shmat");exit(1);

}

/** Now put some things into the memory for the* other process to read.*/s = shm;

for (c = 'a'; c


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/** Finally, we wait until the other process* changes the first character of our memory* to '*', indicating that it has read what* we put there.

*/while (*shm != '*')

sleep(1);

exit(0);}

Output:

$ cc shared30a.c$ ./a.out

Shared Memory Id:622598

ABCDEFGHIJKLMNOPQRSTUVWXYZ

b)shared memory(server)#include #include #include #include #define SHMSZ 27main(){

int shmid;key_t key;char *shm, *s;

/** We need to get the segment named* "5678", created by the server.*/key = 5678;

/** Locate the segment.*/

if ((shmid = shmget(key, SHMSZ, 0666)) < 0) {perror("shmget");exit(1);

}

/** Now we attach the segment to our data space.*/


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if ((shm = shmat(shmid, NULL, 0)) == (char *) -1) {perror("shmat");exit(1);

}

/*

* Now read what the server put in the memory.*/for (s = shm; *s != NULL; s++)

putchar(*s);putchar('\n');

/** Finally, change the first character of the* segment to '*', indicating we have read* the segment.*/*shm = '*';

exit(0);}

Output:

$ cc shared30b.c$ ./a.out

Shared Memory Id:622598

ABCDEFGHIJKLMNOPQRSTUVWXYZ

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