This fantastic. Indeed, this is completely undocumented.<p>Running `grep -R 1000 .` on `apt-get-source cron` turns up:<p><pre><code>        .&#x2F;cron-3.0pl1&#x2F;cron.h:#define	MAX_COMMAND	1000	&#x2F;* max length of internally generated cmd *&#x2F;
</code></pre>
Further grepping for MAX_COMMAND gives you this gem:<p><pre><code>        &#x2F;* Everything up to the next \n or EOF is part of the command...
         * too bad we don&#x27;t know in advance how long it will be, since we
         * need to malloc a string for it... so, we limit it to MAX_COMMAND.
         * XXX - should use realloc().
         *&#x2F; 
        ch = get_string(cmd, MAX_COMMAND, file, &quot;\n&quot;);

</code></pre>
XXX - should use realloc().<p>Really?