Get GNU/Linux user group in C

main.c

#include <stdio.h>
#include <pwd.h>
#include <grp.h>
#include <stdlib.h>

int main(int argc, char *argv[])
{
    struct passwd *pwd;
    struct group *grp;

    if(argc <= 1)
    {
        printf("Add user as second argument\n");
        exit(1);
    }
    pwd = getpwnam(argv[1]);

    if (pwd == NULL)
    {
        printf("Not found user!\n");
    }
    else
    {
        grp = getgrgid(pwd->pw_gid);

        printf("User Info->\nName: %s\nGroup: %s\nHome: %s\nShell: %s\n",
            pwd->pw_name,
            grp->gr_name,
            pwd->pw_dir,
            pwd->pw_shell
        );

        
    }
}