#每次执行脚本时，python会将执行脚本目录加入PYTHONPATH环境变量中(sys.path获取)

#!/usr/bin/python3

import os

import sys

print(sys.path)

print(sys.path[])

执行结果：

[root@localhost tmp]# ./py_test1/pytest24.py

['/tmp/py_test1', '/usr/local/lib/python36.zip', '/usr/local/lib/python3.6', '/usr/local/lib/python3.6/lib-dynload', '/usr/local/lib/python3.6/site-packages', '/usr/local/lib/python3.6/site-packages/pip-9.0.1-py3.6.egg']

/tmp/py_test1

#!/usr/bin/python3

import os

import sys

print(sys.argv[])

执行1结果：

[root@localhost tmp]# ./py_test1/pytest24.py 　　#相对路径执行脚本则会返回相对路径

./py_test1/pytest24.py

执行2结果：

[root@localhost tmp]# /tmp/py_test1/pytest24.py  #绝对路径执行脚本则返回绝对路径

/tmp/py_test1/pytest24.py

#!/usr/bin/python3

import os

import sys

print("sys.argv[0] Output:",sys.argv[])

print("__file Output:",__file__)

执行1结果：

[root@localhost tmp]# ./py_test1/pytest24.py   #相对路径执行脚本则会返回相对路径

sys.argv[] Output: ./py_test1/pytest24.py

__file Output: ./py_test1/pytest24.p

执行2结果：

[root@localhost tmp]# /tmp/py_test1/pytest24.py  #绝对路径执行脚本则会返回绝对路径

sys.argv[] Output: /tmp/py_test1/pytest24.py

__file Output: /tmp/py_test1/pytest24.py

#!/usr/bin/python3

import os

import sys

print("__file Output:",__file__)

print(os.path.abspath(__file__))

print(os.path.realpath(__file__))

执行结果：

[root@localhost tmp]# ./py_test1/pytest24.py

__file Output: ./py_test1/pytest24.py

/tmp/py_test1/pytest24.py

/tmp/py_test1/pytest24.py