Vacation response to test mailers patience

vacation.mail

## OUT OF OFFICE REPLY 
#!/usr/bin/env bash
(gcc -x c - -o vacation && ./vacation) <<EOF
#include <stdio.h>
#include <ctype.h>

static char *rot(char*);

int main()
{
    char VACATION_TIME[] = "V nz ba inpngvba sebz Sev Znl 68 7566 60:55:55 uef.\n"
        "Jbhyq or onpx ng jbex ba Zba Znl 77 7566 54:55:55 uef.\n"
        "Vs lbh ner rkcrpgvat n erfcbafr sebz zr qhevat inpngvba, V fgebatyl oryvrir gung lbh fubhyq nyfb tb bhg ba inpngvba :)\n"
        "Gunaxf sbe lbhe cngvrapr va ernqvat guvf :)\n";
    printf(rot(VACATION_TIME));
    return 0;
}

static char *rot(char *buf)
{
    char *s = buf;
    while(*s)
    {
        if(isalpha(*s))
        {
            int lim = 122;
            if(isupper(*s))
                lim = 90;
            *s += 13;
            if((unsigned char)*s > lim)
            {
                *s -= 26;
            }
        }
        else if(isdigit(*s))
        {
            *s += 5;
            if(*s > 57) *s -= 10;
        }
        ++s;
    }
    return buf;
}
EOF