Raspberry Pi4 uhubctl bash script wont run

Question

Writing a bash script to turn on and off the USB ports on a raspberry pi 4. Using uhubctl.

#!/bin/bash
# Script to turn on and off power to usb port
# Uses uhubctl
#
time_w=5
#cd uhubctl
uhubctl -a off -l 1-1
#
sleep "$time_w"
#
uhubctl -a on -l 1-1
#
echo "All done"

I can run this sudo uhubctl -a off -l 1-1 from the command line without issue.

But if I run the script with sudo bash USB_Power.sh I get the following error.

!o compatible smart hubs detected at location 1-1
Run with -h to get usage info.
All done

Answer 1

uhubctl author here.

To configure udev USB permissions, simply follow uhubctl README. In particular, for Raspberry Pi 4B, you need to add these 2 lines to file /etc/udev/rules.d/52-usb.rules:

SUBSYSTEM=="usb", ATTR{idVendor}=="2109", MODE="0666"
SUBSYSTEM=="usb", ATTR{idVendor}=="1d6b", MODE="0666"

then either reboot or run this command to apply changes live:

sudo udevadm trigger --attr-match=subsystem=usb

Note that you do not need to write any scripts to automate your task. Your script is exactly equivalent to this command:

uhubctl -l 1-1 -a cycle -d 5

Answer 2

I was writing this script in Microsft Visual Studio Code. I forgot that spaces are interperated differently between Windows and Unix when running Bash. So I changed the document settings in Notepad++ to be Unix, re wrote the code and then it runs fine now.

Still have to use sudo because the permissions are not working but not it runs correctly.

More info can be found here

#!/bin/bash
uhubctl -a off -l 1-1
sleep 5
uhubctl -a on -l 1-1
echo "All done"