[英]python sys.argv limitations?
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
可以包含的字符数是否有限制?
MY_INPUT
可以包含的字符类型是否有限制?
关于MY_INPUT
任何其他限制?
更新:我正在使用Ubuntu Linux 10.04
argv
的大小受操作系统的限制,并且从OS到OS的变化很大。 引用Linux execve(2)
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.
Python本身并没有对sys.argv
的长度或内容施加任何限制。 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,就无法完全回答这个问题。
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