strace -v ps -e 2

strace -v ls

neo@netkiller:~/workspace/Document$ strace -c ls
Docbook  makedoc  Tex
% time     seconds  usecs/call     calls    errors syscall
------ ----------- ----------- --------- --------- ----------------
  -nan    0.000000           0        11           read
  -nan    0.000000           0         1           write
  -nan    0.000000           0        38        13 open
  -nan    0.000000           0        27           close
  -nan    0.000000           0        25           fstat
  -nan    0.000000           0        39           mmap
  -nan    0.000000           0        16           mprotect
  -nan    0.000000           0         4           munmap
  -nan    0.000000           0         3           brk
  -nan    0.000000           0         2           rt_sigaction
  -nan    0.000000           0         1           rt_sigprocmask
  -nan    0.000000           0         2           ioctl
  -nan    0.000000           0         9         9 access
  -nan    0.000000           0         1           execve
  -nan    0.000000           0         1           fcntl
  -nan    0.000000           0         2           getdents
  -nan    0.000000           0         1           getrlimit
  -nan    0.000000           0         1           statfs
  -nan    0.000000           0         1           arch_prctl
  -nan    0.000000           0         3         1 futex
  -nan    0.000000           0         1           set_tid_address
  -nan    0.000000           0         1           set_robust_list
------ ----------- ----------- --------- --------- ----------------
100.00    0.000000                   190        23 total
			

neo@netkiller:~/workspace/Document$ strace -f -e open ls >/dev/null
open("/etc/ld.so.cache", O_RDONLY)      = 3
open("/lib/librt.so.1", O_RDONLY)       = 3
open("/lib/libselinux.so.1", O_RDONLY)  = 3
open("/lib/libacl.so.1", O_RDONLY)      = 3
open("/lib/libc.so.6", O_RDONLY)        = 3
open("/lib/libpthread.so.0", O_RDONLY)  = 3
open("/lib/libdl.so.2", O_RDONLY)       = 3
open("/lib/libattr.so.1", O_RDONLY)     = 3
open("/proc/filesystems", O_RDONLY)     = 3
open("/usr/lib/locale/locale-archive", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale/locale.alias", O_RDONLY) = 3
open("/usr/lib/locale/en_US.UTF-8/LC_IDENTIFICATION", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_IDENTIFICATION", O_RDONLY) = 3
open("/usr/lib/gconv/gconv-modules.cache", O_RDONLY) = 3
open("/usr/lib/locale/en_US.UTF-8/LC_MEASUREMENT", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_MEASUREMENT", O_RDONLY) = 3
open("/usr/lib/locale/en_US.UTF-8/LC_TELEPHONE", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_TELEPHONE", O_RDONLY) = 3
open("/usr/lib/locale/en_US.UTF-8/LC_ADDRESS", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_ADDRESS", O_RDONLY) = 3
open("/usr/lib/locale/en_US.UTF-8/LC_NAME", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_NAME", O_RDONLY) = 3
open("/usr/lib/locale/en_US.UTF-8/LC_PAPER", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_PAPER", O_RDONLY) = 3
open("/usr/lib/locale/en_US.UTF-8/LC_MESSAGES", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_MESSAGES", O_RDONLY) = 3
open("/usr/lib/locale/en_US.utf8/LC_MESSAGES/SYS_LC_MESSAGES", O_RDONLY) = 3
open("/usr/lib/locale/en_US.UTF-8/LC_MONETARY", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_MONETARY", O_RDONLY) = 3
open("/usr/lib/locale/en_US.UTF-8/LC_COLLATE", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_COLLATE", O_RDONLY) = 3
open("/usr/lib/locale/en_US.UTF-8/LC_TIME", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_TIME", O_RDONLY) = 3
open("/usr/lib/locale/en_US.UTF-8/LC_NUMERIC", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_NUMERIC", O_RDONLY) = 3
open("/usr/lib/locale/en_US.UTF-8/LC_CTYPE", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_CTYPE", O_RDONLY) = 3
open(".", O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC) = 3