假设我想运行这样的 python 脚本：python my_script.py MY_INPUT。
在这种情况下，MY_INPUT 将被传输到sys.argv[1]。
MY_INPUT 可以包含的字符 个数 有限制吗？
MY_INPUT 可以包含的字符类型是否有限制？
关于MY_INPUT的任何其他限制？
更新：我使用的是 Ubuntu Linux 10.04
【问题讨论】：
MY_INPUT 转到 sys.argv[1]。 sys.argv[0] 将包含 'my_script.py'。
标签： python
argv 的大小受操作系统的限制，并且因操作系统而异。引用 Linux execve(2) 手册页：
Limits on size of arguments and environment
Most Unix implementations impose some limit on the total size
of the command-line argument (argv) and environment (envp)
strings that may be passed to a new program. POSIX.1 allows an
implementation to advertise this limit using the ARG_MAX
constant (either defined in <limits.h> or available at run time
using the call sysconf(_SC_ARG_MAX)).
On Linux prior to kernel 2.6.23, the memory used to store the
environment and argument strings was limited to 32 pages
(defined by the kernel constant MAX_ARG_PAGES). On
architectures with a 4-kB page size, this yields a maximum size
of 128 kB.
On kernel 2.6.23 and later, most architectures support a size
limit derived from the soft RLIMIT_STACK resource limit (see
getrlimit(2)) that is in force at the time of the execve()
call. (Architectures with no memory management unit are
excepted: they maintain the limit that was in effect before
kernel 2.6.23.) This change allows programs to have a much
larger argument and/or environment list. For these
architectures, the total size is limited to 1/4 of the allowed
stack size. (Imposing the 1/4-limit ensures that the new
program always has some stack space.) Since Linux 2.6.25, the
kernel places a floor of 32 pages on this size limit, so that,
even when RLIMIT_STACK is set very low, applications are
guaranteed to have at least as much argument and environment
space as was provided by Linux 2.6.23 and earlier. (This
guarantee was not provided in Linux 2.6.23 and 2.6.24.)
Additionally, the limit per string is 32 pages (the kernel
constant MAX_ARG_STRLEN), and the maximum number of strings is
0x7FFFFFFF.
【讨论】：
type 字符的任何提示？可以给space 吗？可以给tab 吗？
python my_script.py 'This is MY_INPUT as one arg' OtherArg
NUL 字符会终止 argv[] 指针数组指向的每个字符串，因此构造一个包含 '\0' 字节的参数将需要一些努力编码和解码。但是可能有更好的机制来做任何你想做的事情:)
Python 本身对sys.argv 的长度或内容没有任何限制。但是，您的操作系统和/或命令 shell 肯定会。如果不详细考虑您的操作环境，这个问题就无法完全回答。
【讨论】：
sys.maxsize 给出了这个限制。实际上，在创建这么大的列表之前，您的内存就会用完。