Invocation strace |aa0000|*-F* -o /tmp/strace.log| |0000ff|php| |00aa00|test.php| Output 31505 *socket(PF_INET, SOCK_STREAM, IPPROTO_TCP) = 4* 31505 fcntl(*4*, F_SETFL, O_RDONLY|O_NONBLOCK) = 0 31505 connect(*4*, {sa_family=AF_INET, sin_port=htons(9000), sin_addr=inet_addr("127.0.0.1")}, 16) = -1 EINPROGRESS (Operation now in progress) … 31517 execve("/bin/sh", ["sh", "-c", "nohup sleep 30 > /dev/null 2> /d"...], [/\* 51 vars \*/]) = 0 31518 execve("/bin/sleep", ["sleep", "30"], [/\* 51 vars \*/] <unfinished ...> 31505 recvfrom(*4*, "run -i 25\0", 128, 0, NULL, NULL) = 10 31505 *close(4)* = 0 *// XDEBUG CLOSES THE SOCKET* … 31518 <... execve resumed> ) = 0 31518 nanosleep({30, 0}, <unfinished ...> 31518 <... nanosleep resumed> NULL) = 0 31518 close(1) = 0 31518 close(2) = 0 31518 exit_group(0) = ? *// SOCKET IN FORKED PROCESS IS CLOSED* 31518 +++ exited with 0 +++