Hostname ~ # strace stat /etc/mtab 
execve("/usr/bin/stat", ["stat", "/etc/mtab"], [/* 25 vars */]) = 0
brk(0)                                  = 0x509000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2abdd4b39000
uname({sys="Linux", node="Hostname", ...}) = 0
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY)      = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=21386, ...}) = 0
mmap(NULL, 21386, PROT_READ, MAP_PRIVATE, 3, 0) = 0x2abdd4b3a000
close(3)                                = 0
open("/lib/libc.so.6", O_RDONLY)        = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0p\324\1\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1318352, ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2abdd4b40000
mmap(NULL, 2334920, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x2abdd4c3b000
mprotect(0x2abdd4d6c000, 1048576, PROT_NONE) = 0
mmap(0x2abdd4e6c000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x131000) = 0x2abdd4e6c000
mmap(0x2abdd4e71000, 16584, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x2abdd4e71000
close(3)                                = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2abdd4e76000
arch_prctl(ARCH_SET_FS, 0x2abdd4e766d0) = 0
mprotect(0x2abdd4e6c000, 12288, PROT_READ) = 0
mprotect(0x2abdd4c39000, 4096, PROT_READ) = 0
munmap(0x2abdd4b3a000, 21386)           = 0
brk(0)                                  = 0x509000
brk(0x52a000)                           = 0x52a000
lstat("/etc/mtab", 0x7fffd5f8b3a0)      = -1 EACCES (Permission denied)
write(2, "stat: ", 6stat: )                   = 6
write(2, "cannot stat `/etc/mtab\'", 23cannot stat `/etc/mtab') = 23
write(2, ": Permission denied", 19: Permission denied)     = 19
write(2, "\n", 1
)                       = 1
close(1)                                = 0
close(2)                                = 0
exit_group(1)                           = ?
Process 9339 detached