ref: a7ac020664f1de870b09807086565030246ad6fb
dir: /rc/bin/dircp/
#!/bin/rc
# dircp src dest - copy a tree with tar
switch($#*){
case 2
@ {builtin cd $1 && tar cif /fd/1 .} | @ {builtin cd $2 && tar xTf /fd/0}
case *
echo usage: dircp from to >[1=2]
exit usage
}