我下载了一个OctoPi并在我的本地文件系统（EXT4）中解压缩了这个文件：
$ unzip 2014-09-09-wheezy-octopi-0.10.0.zip 只有一个文件被解压缩：
-rwxrwxr-x 1 user user 3276800000 Oct 27 14:46 2014-09-09-wheezy-octopi-0.10.0.img
现在我想为SD卡使用图像，但即使是猫文件写入错误（现在作为根，我试图与用户之前）：
# cat 2014-09-09-wheezy-octopi-0.10.0.img cat: 2014-09-09-wheezy-octopi-0.10.0.img: Operation not permitted
我试图解压缩到另一个位置（不同的FS，USB棒），但它有相同的行为。 我也尝试了strace：
# strace cat 2014-09-09-wheezy-octopi-0.10.0.img execve("/bin/cat", ["cat", "2014-09-09-wheezy-octopi-0.10.0."...], [/* 27 vars */]) = 0 brk(0) = 0x718000 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f1fb2a65000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=166255, ...}) = 0 mmap(NULL, 166255, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f1fb2a3c000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\320\37\2\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1844160, ...}) = 0 mmap(NULL, 3949184, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f1fb2480000 mprotect(0x7f1fb263a000, 2097152, PROT_NONE) = 0 mmap(0x7f1fb283a000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1ba000) = 0x7f1fb283a000 mmap(0x7f1fb2840000, 17024, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f1fb2840000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f1fb2a3b000 mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f1fb2a39000 arch_prctl(ARCH_SET_FS, 0x7f1fb2a39740) = 0 mprotect(0x7f1fb283a000, 16384, PROT_READ) = 0 mprotect(0x60b000, 4096, PROT_READ) = 0 mprotect(0x7f1fb2a67000, 4096, PROT_READ) = 0 munmap(0x7f1fb2a3c000, 166255) = 0 brk(0) = 0x718000 brk(0x739000) = 0x739000 open("/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=3165552, ...}) = 0 mmap(NULL, 3165552, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f1fb217b000 close(3) = 0 fstat(1, {st_mode=S_IFCHR|0600, st_rdev=makedev(136, 1), ...}) = 0 open("2014-09-09-wheezy-octopi-0.10.0.img", O_RDONLY) = -1 EPERM (Operation not permitted) write(2, "cat: ", 5cat: ) = 5 write(2, "2014-09-09-wheezy-octopi-0.10.0."..., 352014-09-09-wheezy-octopi-0.10.0.img) = 35 open("/usr/share/locale/locale.alias", O_RDONLY|O_CLOEXEC) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=2570, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f1fb2a64000 read(3, "# Locale name alias data base.\n#"..., 4096) = 2570 read(3, "", 4096) = 0 close(3) = 0 munmap(0x7f1fb2a64000, 4096) = 0 open("/usr/share/locale/en_US.UTF-8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale/en_US.utf8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale/en_US/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale/en.UTF-8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale/en.utf8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale/en/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale-langpack/en_US.UTF-8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale-langpack/en_US.utf8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale-langpack/en_US/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale-langpack/en.UTF-8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale-langpacsudo k/en.utf8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale-langpack/en/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory) write(2, ": Operation not permitted", 25: Operation not permitted) = 25 write(2, "\n", 1 ) = 1 close(1) = 0 close(2) = 0 exit_group(1) = ? +++ exited with 1 +++
在不同的系统（只检查一个），我能够读取它。
我有最新更新的Kubuntu 14.10 x64。 Linux mycomp 3.16.0-28-generic＃38-Ubuntu SMP Fri Dec 12 17:37:40 UTC 2014 x86_64 x86_64 x86_64 GNU / Linux
其实我通过pipe道（它的作品）写图像：
unzip -p ... | pv | dd ...
但是我想知道， 为什么这个文件不可读，我犯了错误 。
….
后来我有和rapsbian一样的经历：
wget -O 2014-12-24-wheezy-raspbian.zip http://downloads.raspberrypi.org/raspbian_latest
改名
mv 2014-09-09-wheezy-octopi-0.10.0.img initrd.gz
然后做解压