Why C program prints blank line to file?

I have the following C code which writes words given to program to file called "command.txt". If word is "quit" program ends, else it prints the word and writes it to file. However, if the word is "file" it gets the first word on the first line of file by using function getstring() and continues to next loop iteration. This word is then used on this new round and the code goes straight to "else"-branch and should print out the word and write it to file again.

#include<stdio.h>
#include<stdlib.h>
#include<string.h>


void getstring(char **p) {
    char string[100];
    char *word = NULL;
    FILE *file = fopen("command.txt", "r");
    fgets(string, 100, file);
    word = strtok(string," \n");
    p[0] = word;
    fclose(file);
}

void writetofile (char **strarr) {
    FILE *file = fopen("command.txt", "a");
    fprintf(file, "%s\n", strarr[0]);
    fclose(file);
}

int main(void) {

    char line[100];
    char *word = NULL;
    char *strarr[5];
    char **p = NULL;
    int flag = 0, i;

    while (1) {
        if (flag == 1) {
            flag = 0;
        }
        else {
            printf("Give string: ");
            fgets(line, 100, stdin);
            word = strtok(line," \n");
            strarr[0] = word;
        }

        if (strcmp(strarr[0], "quit") == 0) {
            break;
        }
        else if (strcmp(strarr[0], "file") == 0) {
            p = strarr;
            getstring(p);
            flag = 1;
            continue;
        }
        else {
            printf("Text: %s\n", strarr[0]);
            writetofile(strarr);
        }

        for (i=0; i<5; i++) {
            strarr[i] = NULL;
        }
    }   

    return 0;
}

The problem is this: if I type in "file" nothing is written to the file. For example, if I give the words "hello", "file" and "world" and then quit the program the printout looks like this:

Give string: hello
Text: hello
Give string: file
Text: hello
Give string: world
Text: world
Give string: quit

command.txt looks like this:

hello

world

So, there's an empty line where should be another "hello". Why is this? Am I missing something obvious here or is this because of the way pointers are used?