Thread: Making a Shell Problem

i am working a project about Shell in unix.

i want to exe commands like ls, ls < out.txt , sort < in.txt > out.txt

i got a input from the terminal and my program ends while i send EOF.

my ls command doesnt run but the command: ls > out.txt is doing fine. when i am trying to execute ls after this it doesnt work i need to write ls >

i am taking some segmetion faults though

here is some code any help would be appreciated

Code:

Code:

#include "2_shell.h"#include <stdlib.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h> 
#include <unistd.h> 


int main(int argc,char** argv)
{ 




char str[512];
int status;
int i;
pid_t pid, waitPid;
char* hey;


int flag_in=-1,flag_out=-1;
int out; 


char * target_output=">";
char * output;


printf("\n--Welcome to auebshell1--\n");
printf(">");
while(fgets(str,512,stdin)){ 
hey =makeString(str);
char ** tokens=tokenizer(hey,&i);
flag_out=findSympol(tokens,target_output,i);
printf(" output %d ",flag_out); 
if(flag_in<0){
if(flag_out>0){
output=tokens[flag_out+1];
out = open(output,O_WRONLY|O_CREAT,0700); 
dup2(out,STDOUT_FILENO);
close(out);}
}
pid = fork();


if(pid < 0){
perror("ERROR: Child couldnt be created!\n");
return -1;
}
if(pid == 0){








execlp(tokens[0],tokens[0],NULL);
perror("There is no such instruction!!\n");
return -1;
}
else{
waitPid = wait(&status);
if(waitPid == -1){
perror("Failed to wait for child to be executed! \n");
}
}
printf("\n--Welcome to auebshell1--\n");
printf(">"); }
printf(" auebshell terminated!\n"); return 1;
}






























char *makeString(char *input){
int i;
char *returnString;
returnString = (char *)malloc(sizeof(char)*strlen(input)-1);
for(i = 0; i < strlen(input)-1;i++){
returnString[i] = input[i];}




return returnString;


}






char** tokenizer(char* Array,int * a){
int counter=1;
char* *returner=NULL;
char* tokens; 
tokens =strtok(Array," ");
while(tokens){
returner=realloc(returner,sizeof(char*)*counter);


if(returner==NULL)
exit(-1);//memory fail//
returner[counter-1]=tokens;
counter++;
tokens=strtok(NULL," "); }


returner=realloc(returner,sizeof(char*)*(counter));
if(returner==NULL)
exit(-1);
returner[counter]=0;
*a=counter;
return returner;}


int findSympol(char ** Tokens,char * target,int size)
{


int i;
int flag;


for(i=0;i<size;i++){


flag=strcmp(target,Tokens[i]);


if (flag==0) {


thesis=i; 


return thesis;}
}
return thesis;


}

Cross-posted here as well -> Problem with Shell
Neither is properly indented.

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