#include #include #include #include #include #define MAX_LINE

[answerhappygod]

#include <stdio.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <string.h>
#define MAX_LINE 80
typedef struct {
char commandName[15];
int usageCounter;
}
history;
history hist[30];
int count = -1;
void usagedCommands()
{
printf("\nList of usaged command:\n");
int ss,i;
for(ss = 0; ss <= count; ss++)
{
for(i = 0; i< ((count+1) - ss -1); i++)
{
if(hist.usageCounter < hist[i+1].usageCounter)
{
history temp;
temp = hist;
hist = hist[i+1];
hist[i+1] = temp;
}
}
}
if(count <= 10)
{
for(i=0; i<=count; i++)
{
printf("%d.",(i+1));
printf("Command name :%s Usaged count: %d\n", hist.commandName,hist.usageCounter);
}
}
else
{
for(i=0; i<10; i++)
{
printf("%d.",(i+1));
printf("Command name :%s Usaged count: %d\n", hist.commandName,hist.usageCounter);
}
}
printf("\n");
}
int commands(char inputBuffer[], char *args[], int *flag)
{
int length,i,start,count2=0;
length = read(STDIN_FILENO,inputBuffer,MAX_LINE);
start = -1;
if(length == 0)
exit(0);
if(length < 0)
{
printf("Command not read.. \n");
exit(-1);
}
for(i=0;i<length;i++)
{
switch(inputBuffer)
{
case ' ':
case '\t':
if(start != -1)
{
args[count2]=&inputBuffer[start];
count2++;
}
inputBuffer='\0';
start = -1;
break;
case '\n':
if(start != -1)
{
args[count2] = &inputBuffer[start];
count2++;
}
inputBuffer='\0';
start = -1;
break;
default :
if(start == -1)
start = i;
if(inputBuffer[i] == '&')
{

*flag=1;
inputBuffer[i] ='\0';
}
}
}
args[count2] = NULL;
if(strcmp(args[0],"history") == 0)
{
if(count>-1)
usagedCommands();
else
printf("No Commands in the history..\n");
return -1;
}
else if(strcmp(args[0],"exit")==0)
{
exit(0);
}
else
{
count++;
int a = 0;
for(i=0;i<=count;i++)
{
if(strcmp(inputBuffer,hist[i].commandName) == 0)
{
a=1;
hist[i].usageCounter++;
count--;
break;
}
else
{
continue;
}
}
if(a==0)
{
strcpy(hist[count].commandName,inputBuffer);
hist[count].usageCounter=1;
}
}
}
int main(void)
{
char *args[MAX_LINE/2 + 1];
char ss[MAX_LINE];
int should_run = 1;
int i = 0;
int j;
while(should_run)
{
printf("OSH> ");
fflush(stdout);
scanf ("%[^\n]%*c", ss);
printf("input:%s\n",ss);
i = 0;
int j;
args[i] = strtok(ss," ");
while (args[i] != NULL) {
i++;
args[i] = strtok(NULL, " ");
}

if(strcmp(args[0], "exit") == 0)
break;
if(strcmp(args[i-1], "&") != 0)
{
pid_t pid;
pid = fork();
if(pid < 0)
{
fprintf(stderr,"FORK Failed\n");
return 1;
}
else if (pid == 0)
{
execvp(args[0],args);
for(int j=0;j<i;j++)
args[j] = NULL;
}
else
{
wait(NULL);
}
}
else
{
pid_t pid;
pid = fork();
if(pid < 0){
fprintf(stderr,"FORK Failed\n");
return 1;
}
else if (pid == 0){
args[i-1] = NULL;
execvp(args[0],args);
}
else
{
printf("\n\n");
}
}

}
return 0;
}


Please explain this code in words, the entire code