void execute()
{
if(!back)//perform user commands given
{
if(strcmp(command[0],"quit")==0)
exit(0);
else if(strcmp(command[0],"cd")==0)
cd();
else if(strcmp(command[0],"fg")==0)
{
int com=(int)(command[1][0]-'0');
fg(com);
}
else if(strcmp(command[0],"overkill")==0)
overkill();
else if(strcmp(command[0],"pinfo")==0)
{
if(!ch)
{
strcpy(list[p5].process,"pinfo");
list[p5].back=0;
}
if(command[1][0]==0)//if only single argument given with pinfo command
pinfo();
else
{
int i=0,comm1,number=0,num1;
int len1=strlen(command[1]);
if(len1==4)
num1=10*10*10;
else if(len1==3)
num1=10*10;
else if(len1==2)
num1=10;
else if(len1==1)
num1=1;
while(i<len1)
{
comm1=(int)(command[1][i]-'0');
number=num1*comm1+number;
num1=num1/10;
i++;
}
pid1(number);
}
}
else if(strcmp(command[0],"jobs")==0)
{
if(!ch)
{
strcpy(list[p5].process,"jobs");
list[p5].back=0;
}
jobs();
}
else if(strcmp(command[0],"grep")==0)
grep();
else if(strcmp(command[0],"kjob")==0)
{
int comm=command[1][0]-'0';
int comm2=(int)(command[2][0]-'0');
char *c1=command[1][0];
char *c2=command[2][0];
kjob((c1),(c2));
}
else if(strcmp(command[0],"exit")==0)
fprintf(stderr,"The command is quit\n");
else//for system defined commands
{
if(!ch)
{
strcpy(list[p5].process,command[0]);
list[p5].back=0;
}
int returnval=fork();
if(returnval)
{
list[p5++].pid=returnval;
waitpid(returnval,&returnval,0);
}
else
{
int i2=0;
char arguments[101];
char *args[argvals+1];
while(i2<argvals)
{
args[i2]=(char*)malloc(101*sizeof(char));
strcpy(args[i2],command[i2]);
i2++;
}
args[i2]=NULL;
int flag2=1;
if(redir_in)//incase of redirection
{
if(redir_in<argvals -1)
{
freopen(command[redir_in + 1],"r",stdin);
args[redir_in]=NULL;
}
else
{
fprintf(stderr,"Give filename for redirection\n");
exit(0);
}
}
if(redir_out)
{
if(redir_out < argvals -1)
{
freopen(command[redir_out + 1],"w",stdout);
args[redir_out]=NULL;
}
else
{
fprintf(stderr,"Give filename for redirection\n");
exit(0);
}
}
printf("%s",*args);
flag2=0;
execvp(args[0],args);//execute the command in arg
fprintf(stderr,"Not a valid shell command\n");
exit(0);
}
}
}
else
{
if(!ch)
{
strcpy(list[p5].process,command[0]);
list[p5].back=1;
}
int returnval=fork();
if(returnval)
{
if(!ch)
list[p5++].pid=returnval;
printf("Command %s\t Pid %d\n",command[0],returnval);
}
else
{
int i2=0;
int flag3=0;
char *args[argvals];
while(i2<back)
{
args[i2]=(char*)malloc(101*sizeof(char));
strcpy(args[i2],command[i2]);
i2++;
flag3=1;
}
args[i2]=NULL;
execvp(args[0],args);//execute the command in args
fprintf(stderr,"Not a valid Shell command\n");
exit(0);
}
}
}
int main(void)
{
char line[1024];
int mode;
process * root;
char curDir[100];
getcwd(curDir,100);
pinfo *head;
head=NULL;
while (1)
{
global_pipes=0;
initials(curDir);
mode=0;
fflush(stdin);
fflush(stdout);
gets(line); /* read in the command line */
//printf("line ==%s\n",line);
if (*line == '\0')
continue;
printf("\n");
int i=0;
while((line[i]) != '\0')
{
if(line[i] == '&')
{
mode++;
//line[i]='\0';
}
i++;
}
//jobs
if(strcmp(line, "jobs") == 0)
{
head=display(head);
continue;
}
root=parse(line);
/*
int p=0;
while(argv[p] != NULL)
{
printf("argv = %s\n",argv[p]);
p++;
}
p=0 ;
while(out[p] !=NULL)
{
printf("out = %s\n",root->out);
p++;
}
p=0 ;
while(in[p] !=NULL)
{
printf("in = %s\n",root->in);
p++;
}
*/
//pinfo
if(strcmp(line, "pinfo") == 0)
{
fflush(stdin);
fflush(stdout);
ppinfo(root-> argv);
continue;
}
//overkill
if(strcmp(root->argv[0],"overkill")==0)
{
head=overkill(head);
continue;
}
//fg
else if(strcmp(root->argv[0],"fg")==0)
{
head=fg(head,root->argv);
continue;
}
//kjob
else if(strcmp(root->argv[0],"kjob")==0)
{
head=kjob(head,root->argv);
continue;
}
//exit
else if (strcmp(root->argv[0], "quit") == 0)
exit(0);
//cd
if (strcmp(root->argv[0], "cd") == 0)
{
chdir(root->argv[1]);
continue;
}
else
{ if(global_pipes != 0)
head=executepipes(root,head,mode);
else
head=execute(root,head,mode);
}
}
}