def main():
    print "Hello"

if __name__=='__main__':
    main()
world.py

def main():
    print "Hello"

if __name__=='__main__':
    main()

python hello.py
python world.py

　　hello
　　world

import sys

def main():
    try:
        print "hello"
        sys.exit(0)
    except:
        sys.exit(1)

if __name__=='__main__':
    main()

python hello.py
if [ $?==0 ];then
    exit
else
        python world.py       
fi