1 #include <stdio.h> 2 #include <stdlib.h> 3 4 extern char** environ; 5 printenv_main(int argc,char ** argv)6int printenv_main (int argc, char **argv) 7 { 8 char** e; 9 char* v; 10 int i; 11 12 if (argc == 1) { 13 e = environ; 14 while (*e) { 15 printf("%s\n", *e); 16 e++; 17 } 18 } else { 19 for (i=1; i<argc; i++) { 20 v = getenv(argv[i]); 21 if (v) { 22 printf("%s\n", v); 23 } 24 } 25 } 26 27 return 0; 28 } 29 30