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Hi, I am trying to get permission to /dev/ttyUSB0
ls -l /dev/tty* gives me
crw-rw---- 1 root uucp 188, 0 2009-12-03 17:25 /dev/ttyUSB0
groups session (my username) gives me
wheel network video audio optical storage users uucp mpd
I can't find the problem.
Login as root and there is no problem at all?
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I just had to work this out so that I could connect with my 3G modem (which uses /dev/ttyUSB0) without having to login as root (or sudo or su). I needed a udev rule.
First, I copied /lib/udev/rules.d/50-udev-default.rules to /etc/udev/rules.d/50-udev-default.rules since I didn't have a copy there to start with. According to the udev man pages, the rules in /lib are the system defaults, while the ones in the /etc subfolder are customised ones.
Then after the rule for serial devices I added a specific rule just for ttyUSB0 with relaxed permissions:
# serial
# this is the general rule that covers ttyUSB0 among others
KERNEL=="tty[A-Z]*[0-9]|pppox[0-9]*|ircomm[0-9]*|noz[0-9]*|rfcomm[0-9]*", GROUP="uucp"
# relax the permissions just for ttyUSB0
KERNEL=="ttyUSB0", MODE="0666"
After that I just needed to unplug the modem and reconnect it, so that udev could recreate the device with the new permissions.
Doing this means I didn't have to add my normal user to the uucp group since I have read that doing so creates security issues. But then giving everyone rw access to ttyUSB0 probably creates security issues as well.
Hope that helps.
DC
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