After every reboot I have to set chmod o+rw /dev/ttyS0 to be able to print to my POS printer via serial port in bash.
Is it possible to save permissions and also baud rate, bits, stop bit and parity after the device is closed?
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you can check the group owner of /dev/ttyS0 with:
ls -l /dev/ttyS0
and then add your user in this group:
usermod -a -G {group-name} username
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... as long as one isn't on one of the operating systems where serial terminals have group
wheel. This hasn't answered what the questioner asked about line speed and framing, by the way. – JdeBP Jan 17 '17 at 12:45 -
Btw.
useraddis for a new user. I am an existing user. I have to usesudo usermod -a -G dialout my_username. Then I can confirm it with the commandgroups my_username. I just found this becauseuseradddidn't work – Hrvoje T Jan 17 '17 at 22:44 -
ls /dev/ttyS0? – ctrl-alt-delor Jan 17 '17 at 10:51/devsubtree is not persistent, but it is generated at boot byudev. – AlexP Jan 17 '17 at 10:58crw-rw---- 1 root dialout 4, 64 Sij 17 09:15 /dev/ttyS0after boot and then I change it tocrw-rw-rw- 1 root dialout 4, 64 Sij 17 09:15 /dev/ttyS0that I can print from bash – Hrvoje T Jan 17 '17 at 11:01dialout, it is also more secure. – ctrl-alt-delor Jan 17 '17 at 11:02