通过 os.system 推送
问题描述
我正在使用 crontab 为我的 minecraft 服务器运行维护脚本.大多数时候它工作正常，除非 crontab 尝试使用重启脚本.如果我手动运行重新启动脚本，则没有任何问题.因为我相信它与路径名有关，所以我试图确保它总是从 minecraft 目录执行任何 minecraft 命令.所以我将命令封装在 pushd/popd 中:
I'm using a crontab to run a maintenance script for my minecraft server. Most of the time it works fine, unless the crontab tries to use the restart script. If I run the restart script manually, there aren't any issues. Because I believe it's got to do with path names, I'm trying to make sure it's always doing any minecraft command FROM the minecraft directory. So I'm encasing the command in pushd/popd:
os.system("pushd /directory/path/here")
os.system("command to sent to minecraft")
os.system("popd")
下面是一个交互式会话，将我的世界从等式中剔除.一个简单的ls"测试.如您所见，它根本没有从 pushd 目录运行 os.system 命令，而是从/etc/运行 python 来说明我的观点的目录.显然 pushd 不能通过 python 工作，所以我想知道我还能如何实现这一目标.谢谢！
Below is an interactive session taking minecraft out of the equation. A simple "ls" test. As you can see, it does not at all run the os.system command from the pushd directory, but instead from /etc/ which is the directory in which I was running python to illustrate my point.Clearly pushd isn't working via python, so I'm wondering how else I can achieve this. Thanks!
>>> def test():
... import os
... os.system("pushd /home/[path_goes_here]/minecraft")
... os.system("ls")
... os.system("popd")
...
>>> test()
~/minecraft /etc
DIR_COLORS cron.weekly gcrypt inputrc localtime mime.types ntp ppp rc3.d sasldb2 smrsh vsftpd.ftpusers
DIR_COLORS.xterm crontab gpm-root.conf iproute2 login.defs mke2fs.conf ntp.conf printcap rc4.d screenrc snmp vsftpd.tpsave
X11 csh.cshrc group issue logrotate.conf modprobe.d odbc.ini profile rc5.d scsi_id.config squirrelmail vz
adjtime csh.login group- issue.net logrotate.d motd odbcinst.ini profile.d rc6.d securetty ssh warnquota.conf
aliases cyrus.conf host.conf java lvm mtab openldap protocols redhat-release security stunnel webalizer.conf
alsa dbus-1 hosts jvm lynx-site.cfg multipath.conf opt quotagrpadmins resolv.conf selinux sudoers wgetrc
alternatives default hosts.allow jvm-commmon lynx.cfg my.cnf pam.d quotatab rndc.key sensors.conf sysconfig xinetd.conf
bashrc depmod.d hosts.deny jwhois.conf mail named.caching-nameserver.conf passwd rc rpc services sysctl.conf xinetd.d
blkid dev.d httpd krb5.conf mail.rc named.conf passwd- rc.d rpm sestatus.conf termcap yum
cron.d environment imapd.conf ld.so.cache mailcap named.rfc1912.zones pear.conf rc.local rsyslog.conf setuptool.d udev yum.conf
cron.daily exports imapd.conf.tpsave ld.so.conf mailman netplug php.d rc.sysinit rwtab shadow updatedb.conf yum.repos.d
cron.deny filesystems init.d ld.so.conf.d makedev.d netplug.d php.ini rc0.d rwtab.d shadow- vimrc
cron.hourly fonts initlog.conf libaudit.conf man.config nscd.conf pki rc1.d samba shells virc
cron.monthly fstab inittab libuser.conf maven nsswitch.conf postfix rc2.d sasl2 skel vsftpd
sh: line 0: popd: directory stack empty
===(CentOS 服务器与 python 2.4)
=== (CentOS server with python 2.4)
解决方案
每个 shell 命令都在单独的进程中运行.它生成一个 shell，执行 pushd 命令，然后 shell 退出.
Each shell command runs in a separate process. It spawns a shell, executes the pushd command, and then the shell exits.
只需在同一个 shell 脚本中编写命令:
Just write the commands in the same shell script:
os.system("cd /directory/path/here; run the commands")
更好的(也许)方法是使用 subprocess 模块:
A nicer (perhaps) way is with the subprocess module:
from subprocess import Popen
Popen("run the commands", shell=True, cwd="/directory/path/here")
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