mkdirz toexecute
echo echo $$ > toexecute/ppid
chmod +x toexecute/ppid
toexecute/ppid > toexecute/pid1
toexecute/ppid > toexecute/pid2
diff -q toexecute/pid1 toexecute/pid2
erase toexecute/ppid
erase toexecute/pid1
erase toexecute/pid2
rmdirz toexecute