Padding printf for Strings by 0

Question

Is there a way to replace the space character to 0 in printf padding for field width

Code used

printf("%010s","this");

Doesnt seem to work for strings!!

Answer 1

Indeed, the 0 flag only works for numeric conversions. You will have to do this by hand:

int print_padleftzeroes(const char *s, size_t width)
{
    size_t n = strlen(s);
    if(width < n)
        return -1;
    while(width > n)
    {
        putchar('0');
        width--;
    }
    fputs(s, stdout);
    return 0;
}

Answer 2

what about

 test="ABCD"
 printf "%0$(expr 9 - ${#test})d%s" 0 $test

that will give you what you need too.

 ~:00000ABCD

or is you want to padd with other numbers just change

  printf "%0$(expr 9 - ${#test})d%s" 1 $test

will give you

 ~:11111ABCD