#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
void parseCmd(char* cmd, char** params);
int executeCmd(char** params);
#define MAX_COMMAND_LENGTH 100
#define MAX_NUMBER_OF_PARAMS 10
int main()
{
char cmd[MAX_COMMAND_LENGTH + 1];
char* params[MAX_NUMBER_OF_PARAMS + 1];
int cmdCount = 0;
while(1) {
// Print command prompt
char* username = getenv("USER");
printf("%s@shell %d> ", username, ++cmdCount);
// Read command from standard input, exit on Ctrl+D
if(fgets(cmd, sizeof(cmd), stdin) == NULL) break;
// Remove trailing newline character, if any
if(cmd[strlen(cmd)-1] == '\n') {
cmd[strlen(cmd)-1] = '\0';
}
// Split cmd into array of parameters
parseCmd(cmd, params);
// Exit?
if(strcmp(params[0], "exit") == 0) break;
// Execute command
if(executeCmd(params) == 0) break;
}
return 0;
}
// Split cmd into array of parameters
void parseCmd(char* cmd, char** params)
{ int i=0;
for(i = 0; i < MAX_NUMBER_OF_PARAMS; i++) {
params[i] = strsep(&cmd, " ");
if(params[i] == NULL) break;
}
}
int executeCmd(char** params)
{
// Fork process
pid_t pid = fork();
// Error
if (pid == -1) {
char* error = strerror(errno);
printf("fork: %s\n", error);
return 1;
}
// Child process
else if (pid == 0) {
// Execute command
execvp(params[0], params);
// Error occurred
char* error = strerror(errno);
printf("shell: %s: %s\n", params[0], error);
return 0;
}
// Parent process
else {
// Wait for child process to finish
int childStatus;
waitpid(pid, &childStatus, 0);
return 1;
}
}Customize Terminal for Linux (Written in C language )
