All attempts at modifying a file leads to 'Permission denied'

Question

I was trying to increase my mouse scroll speed by following https://github.com/tkkcc/libinput_patch which requires modifying a file. Should be easy...

$ echo 6 > /tmp/libinput_discrete_deltay_multiplier
bash: /tmp/libinput_discrete_deltay_multiplier: Permission denied

Nothing a sudo wont solve right?

$ sudo bash -c 'echo "6" > /tmp/libinput_discrete_deltay_multiplier'
bash: line 1: /tmp/libinput_discrete_deltay_multiplier: Permission denied

Checks permisions

$ stat  /tmp/libinput_discrete_deltay_multiplier
Access: (0666/-rw-rw-rw-)

At this moment I'm at the limit of my abilities. How can I change this file and why it doesn't let me change it even with root privileges? I tried many approaches and search engines are no good on this one.

Edit: Tried

$ echo 6 | sudo tee /tmp/libinput_discrete_deltay_multiplier
tee: /tmp/libinput_discrete_deltay_multiplier: Permission denied

$ dmesg | tail
dmesg: read kernel buffer failed: Operation not permitted

Does this answer your question? Redirecting stdout to a file you don't have write permission on — Andy Dalton, Jul 07 '21 at 20:25
tee: /tmp/libinput_discrete_deltay_multiplier: Permission denied. sadly I tried with tee already — welkam, Jul 07 '21 at 21:01
Can you post your exact command with tee? The answers in the link posted by @AndyDalton work for me, even after changing the permissions to 0600 and owned by root. — ajgringo619, Jul 07 '21 at 22:05
@AndyDalton, note that what they're doing there with sudo is to have the sudo'ed Bash do the redirection, essentially the as in this answer in that same question. — ilkkachu, Jul 07 '21 at 23:06
If it's Linux, check lsattr /tmp/libinput_discrete_deltay_multiplier. Also mount or findmnt to check what file system /tmp is (or / if /tmp is part of it) — ilkkachu, Jul 07 '21 at 23:08
This is strange lsattr /tmp/libinput_discrete_deltay_multiplier lsattr: Operation not supported While reading flags on /tmp/libinput_discrete_deltay_multiplier — welkam, Jul 07 '21 at 23:11
Seems this one: https://unix.stackexchange.com/q/503111/315749. To make sure, and to also make this Q more likely to help other users, could you please add the output of ls -l /tmp/libinput_discrete_deltay_multiplier (to see the file's owner and group) to it? Also, what operating system are you using? — fra-san, Jul 08 '21 at 05:42
...and the output of ls -l /tmp would be useful too, to make sure it is a sticky directory everyone can write to. A way to write to that file should then be to impersonate the file owner: sudo -u file_owner sh -c 'echo 6 > /tmp/...' — fra-san, Jul 08 '21 at 05:57
Please don't edit the question to include the answer - I have rolled back that edit so that the question conforms with site guidelines. The link to the duplicate is meant to guide visitors to the solution. — AdminBee, Jul 08 '21 at 10:35

All attempts at modifying a file leads to 'Permission denied'

0 Answers0