@!/usr/bin/env: 当我尝试使用 ros 节点时没有这样的文件或目录

Question

I tried to write a subscriber and publisher node; but when I try to run the publisher with rosrun , it gives me an error: @!/usr/bin/env: No such file or directory

Here is the error and the corresponding code (I did chmod +x ):

Publisher node:

@!/usr/bin/env python

import rospy
from std_msgs.msg import String

def publish_it():
    pub = rospy.Publisher("first_msgs",String , queue_size = 10)
    rospy.init_node("publisher_node",anonymous = True)
    x = 1
    z = 10
    rate = rospy.Rate(z) #1/z sec delay

    while not rospy.is_shutdown():
        x += 1
        if x == 100:
            x = 0

        msg = "Hi this is our first message . times:" + str(x)
        rospy.loginfo(msg)
        pub.publish(msg)
        rate.sleep()

if __name__ == "__main__":
    try:
        publish_it()
    except rospy.ROSInterruptException:
        pass

Subscriber node:

@!/usr/bin/env python

import rospy
from std_msgs.msg import String

def callback(data):
    rospy.loginfo(data.data)

def iSeeIt():
    rospy.init_node("subscriber_node",anonymous = True)
    rospy.Subscriber("first_msgs",String,callback)
    rospy.spin()

if __name__ == "__main__":
    iSeeIt()

Answer 1

You are misusing the shebang construct. Instead of using @! you have to write #! , followed by the interpreter which should be applied to your code. Furthermore, the line (ie #!/usr/bin/env python ) needs to be in the first row of your script. Thus, the head of your subscriber node should look like this:

#!/usr/bin/env python
# subscriber node

import rospy
from std_msgs.msg import String
...

Answer 2

rospy init must be placed before the publisher, and your code shebang should be as the following:

#!/usr/bin/env python

import rospy
from std_msgs.msg import String

def publish_it():
    rospy.init_node("publisher_node", anonymous=True)
    pub = rospy.Publisher("first_msgs", String, queue_size=10)
    x = 1
    z = 10
    rate = rospy.Rate(z)
    ....

---

[NOTE]:

• Make sure the Python script is executable ( chmod +x mypythonscript.py )
• If you are using Python3 in ROS using this shebang ( #!/usr/bin/python3 or #!/usr/bin/env python3 ) instead.

Answer 3

Thank you guys, i solved it by changing @!/usr/bin/env python with #!/usr/bin/python2.7 . I am using python3 and i don't really understand how it works but i works

Answer 4

sudo apt-get install python-is-python3

write this code it will be solve your problem