在哪里可以找到所有 subprocess.call() 代码 (0,1,2 ..)？
Where can I find all the subprocess.call() codes (0,1,2 ..)?
我是运行下面的Python代码，查了subprocess的文档还是没有找到代码图：
import pkg_resources
from subprocess import call
packages = [dist.project_name for dist in pkg_resources.working_set]
call("sudo pip3 install --upgrade " + ' '.join(packages), shell=True)
输出：2
2 是什么意思？有时它是 0 或 1。
shell 脚本或用户执行的每个 Linux 命令都有一个退出状态。
Linux 手册页统计了每个命令的退出状态。
- 0 退出状态表示命令成功，没有任何错误。
- 非零（1-255 个值）退出状态表示命令失败。
典型的信号是：
0 – Success.
1 – A built-in command failure.
2 – A syntax error has occurred.
3 – Signal received that is not trapped.
某些退出状态值已保留用于特殊用途：
126 - A file to be executed was found, but it was not an executable utility.
127 - A utility to be executed was not found.
128 - A command was interrupted by a signal.
负值 -N 表示子进程被信号 N 终止（仅 POSIX）。
代码是特定于平台的，例如 Windows:
0 - Success
1 - Invalid function
2 - File not found
3 - Path not found
4 - Too many open files
来自python doc:
Some systems have a convention for assigning specific meanings to
specific exit codes, but these are generally underdeveloped; Unix
programs generally use 2 for command line syntax errors and 1 for all
other kind of errors.
我是运行下面的Python代码，查了subprocess的文档还是没有找到代码图：
import pkg_resources
from subprocess import call
packages = [dist.project_name for dist in pkg_resources.working_set]
call("sudo pip3 install --upgrade " + ' '.join(packages), shell=True)
输出：2
2 是什么意思？有时它是 0 或 1。
shell 脚本或用户执行的每个 Linux 命令都有一个退出状态。
Linux 手册页统计了每个命令的退出状态。
- 0 退出状态表示命令成功，没有任何错误。
- 非零（1-255 个值）退出状态表示命令失败。
典型的信号是：
0 – Success.
1 – A built-in command failure.
2 – A syntax error has occurred.
3 – Signal received that is not trapped.
某些退出状态值已保留用于特殊用途：
126 - A file to be executed was found, but it was not an executable utility.
127 - A utility to be executed was not found.
128 - A command was interrupted by a signal.
负值 -N 表示子进程被信号 N 终止（仅 POSIX）。
代码是特定于平台的，例如 Windows:
0 - Success
1 - Invalid function
2 - File not found
3 - Path not found
4 - Too many open files
来自python doc:
Some systems have a convention for assigning specific meanings to specific exit codes, but these are generally underdeveloped; Unix programs generally use 2 for command line syntax errors and 1 for all other kind of errors.