與 python 中的 os.system(cmd) 傳回值與linux 命令傳回值對應關係

一、python中的 os.system(cmd)的傳回值與linux命令傳回值（具體參見本文附加內容）的關係

大家都習慣用os.systemv()函數執行linux命令，該函數的傳回值十進位數（分別對應一個16位的位元）。該函數的傳回值與linux命令傳回值兩者的轉換關係為：該函數的傳回值（十進位）轉化成16位元，截取其高八位（如果低位元是0的情況下，有關作業系統的錯誤碼共131個，所以低位都是零），然後轉乘十進位數即為 linux命令傳回值0。

例如：

os.system()傳回值為0                      linux命令傳回值也為0.

os.system()傳回值為256，十六位位元示為：00000001，00000000，高八位轉乘十進位為 1           對應   linux命令傳回值 1

os.system()傳回值為512，十六位位元示為：00000010，00000000，高八位轉乘十進位為 2           對應   linux命令傳回值 2

......其它同理

os.system()傳回值為32512，十六位位元示為：01111111，00000000，高八位轉乘十進位為 127          對應   linux命令傳回值 127

........

或者簡單說，linux命令返回碼 左移8位，然後轉換成十進位就變成了 os.system()函數的傳回值了。

附加內容

linux命令的傳回值

linux命令執行後無論成功與否都有一個傳回值：

如果為 0，則表示命令執行成功

其它值則表示錯誤，具體的錯誤碼含義如下：

 "OS error code   1:  Operation not permitted" "OS error code   2:  No such file or directory" "OS error code   3:  No such process" "OS error code   4:  Interrupted system call" "OS error code   5:  Input/output error" "OS error code   6:  No such device or address" "OS error code   7:  Argument list too long" "OS error code   8:  Exec format error" "OS error code   9:  Bad file descriptor" "OS error code  10:  No child processes" "OS error code  11:  Resource temporarily unavailable" "OS error code  12:  Cannot allocate memory" "OS error code  13:  Permission denied" "OS error code  14:  Bad address" "OS error code  15:  Block device required" "OS error code  16:  Device or resource busy" "OS error code  17:  File exists" "OS error code  18:  Invalid cross-device link" "OS error code  19:  No such device" "OS error code  20:  Not a directory" "OS error code  21:  Is a directory" "OS error code  22:  Invalid argument" "OS error code  23:  Too many open files in system" "OS error code  24:  Too many open files" "OS error code  25:  Inappropriate ioctl for device" "OS error code  26:  Text file busy" "OS error code  27:  File too large" "OS error code  28:  No space left on device" "OS error code  29:  Illegal seek" "OS error code  30:  Read-only file system" "OS error code  31:  Too many links" "OS error code  32:  Broken pipe" "OS error code  33:  Numerical argument out of domain" "OS error code  34:  Numerical result out of range" "OS error code  35:  Resource deadlock avoided" "OS error code  36:  File name too long" "OS error code  37:  No locks available" "OS error code  38:  Function not implemented" "OS error code  39:  Directory not empty" "OS error code  40:  Too many levels of symbolic links" "OS error code  42:  No message of desired type" "OS error code  43:  Identifier removed" "OS error code  44:  Channel number out of range" "OS error code  45:  Level 2 not synchronized" "OS error code  46:  Level 3 halted" "OS error code  47:  Level 3 reset" "OS error code  48:  Link number out of range" "OS error code  49:  Protocol driver not attached" "OS error code  50:  No CSI structure available" "OS error code  51:  Level 2 halted" "OS error code  52:  Invalid exchange" "OS error code  53:  Invalid request descriptor" "OS error code  54:  Exchange full" "OS error code  55:  No anode" "OS error code  56:  Invalid request code" "OS error code  57:  Invalid slot" "OS error code  59:  Bad font file format" "OS error code  60:  Device not a stream" "OS error code  61:  No data available" "OS error code  62:  Timer expired" "OS error code  63:  Out of streams resources" "OS error code  64:  Machine is not on the network" "OS error code  65:  Package not installed" "OS error code  66:  Object is remote" "OS error code  67:  Link has been severed" "OS error code  68:  Advertise error" "OS error code  69:  Srmount error" "OS error code  70:  Communication error on send" "OS error code  71:  Protocol error" "OS error code  72:  Multihop attempted" "OS error code  73:  RFS specific error" "OS error code  74:  Bad message" "OS error code  75:  Value too large for defined data type" "OS error code  76:  Name not unique on network" "OS error code  77:  File descriptor in bad state" "OS error code  78:  Remote address changed" "OS error code  79:  Can not access a needed shared library" "OS error code  80:  Accessing a corrupted shared library" "OS error code  81:  .lib section in a.out corrupted" "OS error code  82:  Attempting to link in too many shared libraries" "OS error code  83:  Cannot exec a shared library directly" "OS error code  84:  Invalid or incomplete multibyte or wide character" "OS error code  85:  Interrupted system call should be restarted" "OS error code  86:  Streams pipe error" "OS error code  87:  Too many users" "OS error code  88:  Socket operation on non-socket" "OS error code  89:  Destination address required" "OS error code  90:  Message too long" "OS error code  91:  Protocol wrong type for socket" "OS error code  92:  Protocol not available" "OS error code  93:  Protocol not supported" "OS error code  94:  Socket type not supported" "OS error code  95:  Operation not supported" "OS error code  96:  Protocol family not supported" "OS error code  97:  Address family not supported by protocol" "OS error code  98:  Address already in use" "OS error code  99:  Cannot assign requested address" "OS error code 100:  Network is down" "OS error code 101:  Network is unreachable" "OS error code 102:  Network dropped connection on reset" "OS error code 103:  Software caused connection abort" "OS error code 104:  Connection reset by peer" "OS error code 105:  No buffer space available" "OS error code 106:  Transport endpoint is already connected" "OS error code 107:  Transport endpoint is not connected" "OS error code 108:  Cannot send after transport endpoint shutdown" "OS error code 109:  Too many references: cannot splice" "OS error code 110:  Connection timed out" "OS error code 111:  Connection refused" "OS error code 112:  Host is down" "OS error code 113:  No route to host" "OS error code 114:  Operation already in progress" "OS error code 115:  Operation now in progress" "OS error code 116:  Stale NFS file handle" "OS error code 117:  Structure needs cleaning" "OS error code 118:  Not a XENIX named type file" "OS error code 119:  No XENIX semaphores available" "OS error code 120:  Is a named type file" "OS error code 121:  Remote I/O error" "OS error code 122:  Disk quota exceeded" "OS error code 123:  No medium found" "OS error code 124:  Wrong medium type" "OS error code 125:  Operation canceled" "OS error code 126:  Required key not available" "OS error code 127:  Key has expired" "OS error code 128:  Key has been revoked" "OS error code 129:  Key was rejected by service" "OS error code 130:  Owner died" "OS error code 131:  State not recoverable"