Making own shell in C -

i'm trying make own shell in c, having trouble strtok. use correctly parse out command , arguments input, can't parse path (it segfaults). once path parsed correctly should able call execlp on each piece , fork processes accordingly. insight appreciated, code below. feel free comment on style choices if think there doing better.

#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <string.h>  void parse(char *, char *); void process(char *, char *, int);  int main(int argc, char *argv[]) {   char *command;   char *path;   char buffer[1024];   command = (char *)malloc(sizeof(char));   path = (char *)malloc(sizeof(char));   int loop = 1;   while(loop == 1){     path = getenv("mypath");     if(path == null)       path = "/bin#.";     printf("($mypath %s)\n", path);      printf("myshell$ ");     command = fgets(buffer, 1024, stdin);     printf("buffer: %s", buffer);     printf("command: %s", command);      if(strcmp(command,"exit\n") == 0 || strcmp(command, "quit\n") == 0){       loop = 0;       printf("program terminated\n");     }     parse(command, path);   }   return 0; }  void parse(char *command, char *path){   char *argv;   int argnum = 0;   argv = strtok(command, " ");   while(argv != null){     printf("%s %d\n", argv, argnum);     argv = strtok (null, " ");     argnum++;     }   printf("calling...\n");   process(argv, path, argnum);   printf("called\n"); }  void process(char *argv, char *path, int argnum){   char *pathpiece;   int pathnum = 0;   pathpiece = strtok(path, "#");   while(pathpiece != null){     printf("%s %d\n", pathpiece, pathnum);     pathpiece = strtok(null, "#");     pathnum++;   } } 

you're setting path point read-only memory location, , calling strtok on cause of problems when strtok attempts tokenize (i.e. write null character somewhere inside it).

you need like:

char path[1024]; 

and call strcpy like:

strcpy(path, getenv("mypath")); 

and

strcpy(path, "/bin#."); 

i suggest read on string handling in c.