[英]How to access python return value from bash script
I'm trying to understand how to access from a bash script the return value of a python script. 我试图了解如何从bash脚本访问python脚本的返回值。
Clarifying through an example: 澄清一个例子:
foo.py foo.py
def main():
print ("exec main..")
return "execution ok"
if __name__ == '__main__':
main()
start.sh start.sh
script_output=$(python foo.py 2>&1)
echo $script_output
If I run the bash script, this prints the message "exec main..". 如果我运行bash脚本,则会打印消息“exec main ..”。
How can I store in script_output the return value ( execution ok )? 如何在script_output中存储返回值( 执行正常 )? If I direct execution ok to stdout, the script_output will capture all the stdout (so the 2 print statement).
如果我直接执行ok到stdout,script_output将捕获所有stdout(所以2 print语句)。
Is there any way to implement this? 有没有办法实现这个?
Thanks! 谢谢! Alessio
阿莱西奥
Add a proper exit code from your script using the sys.exit()
module. 使用
sys.exit()
模块从脚本中添加适当的退出代码。 Usually commands return 0 on successful completion of a script. 通常,命令在成功完成脚本后返回0。
import sys
def main():
print ("exec main..")
sys.exit(0)
and capture it in shell script with a simple conditional. 并使用简单的条件在shell脚本中捕获它。 Though the exit code is 0 by default and need not be passed explicitly, using
sys.exit()
gives control to return non-zero codes on error cases wherever applicable to understand some inconsistencies with the script. 虽然退出代码为0默认情况下, 不需要使用显式传递,
sys.exit()
将控制权交给出错的情况下返回非零代码(如适用),了解一些不一致的脚本。
if python foo.py 2>&1 >/dev/null; then
echo 'script ran fine'
fi
You can get the previous command's output status through $?
您可以通过
$?
获取上一个命令的输出状态$?
. 。 If the python script ran successfully without any
stderr
, it should return 0
as exit code else it would return 1
or any number other than 0. 如果python脚本在没有任何
stderr
情况下成功运行,它应该返回0
作为退出代码,否则它将返回1
或除0以外的任何数字。
#!/bin/bash
python foo.py 2>&1 /dev/null
script_output=$?
echo $script_output
Bash contains only return code in $?
Bash只包含
$?
返回码$?
, so you can't use it to print the text from python's return
. ,所以你不能用它来打印python
return
的文本。 My solution is write in to the stderr in python script, next print only stderr in bash: 我的解决方案是在python脚本中写入stderr,接下来只打印bash中的stderr:
import sys
def main():
print ("exec main..")
sys.stderr.write('execution ok\n')
return "execution ok"
if __name__ == '__main__':
main()
Bash: 击:
#!/bin/bash
script_output=$(python foo.py 1>/dev/null)
echo $script_output
Output: 输出:
execution ok
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