$ echo foobar | strace rot13
 -> 1
[4:5] execve("rot13", 0x00007fffff001008, (NULL)) -> 0
[4:5] mmap((NULL), 16777216, 3, 8, -1, 0) -> 0x700000000000
[4:5] read(0, 0x00007ffffeffff28, 128) -> 8
[4:5] write(1, 0x00007ffffeffff28, 8)sbbone 
 -> 8
[4:5] read(0, 0x00007ffffeffff28, 128) -> 0
[4:5] exit(0)$ 
$