I have a udev rule that will run a shell script to create a directory and mount a device in read-only mode. The problem is that when the rule runs (when I insert the device), it creates the directory but doesn't mount the device. Naturally, something must be wrong with the script then. However, I can run the script (I insert the device, delete the directory that is created by the udev rule manually, then run the script manually as well) and it creates the directory and mounts the device just fine. Relevant section of udev rule (filename = '10-magicusb.rules'): ENV{MYMOUNT}==&quot;1&quot;, RUN+=&quot;/etc/udev/scripts/romount.sh&quot;  romount.sh: #!/bin/bash mkdir /media/sdb1 /bin/mount /dev/sdb1 -o ro,noatime /media/sdb1  Technically the device name comes from further up in the udev rule (its not hardcoded, trust me). I run a script that creates romount.sh and I pass that script the device with %k. However, that shouldn't be related since the script runs from udev, but stops halfway through execution. My guess is there is some timing issue going on here. When the rule runs, for some reason it cannot mount the device, but when I do it later manually the system has had time to sort things out I guess. I added a sleep 10 to the top of the bash script to no avail. Thank you in advance. EDIT 1 Based on what David G. has posted, I did some testing with the improved script so now romount.sh looks like this: #!/bin/bash mkdir /media/sdb1 (     echo 'before while iteration' &gt; /etc/udev/scripts/iteration.txt     while [[ ! -b /dev/sdb1 ]]     do         sleep 1         echo 'iteration performed' &gt; /etc/udev/scripts/iteration.txt     done     /bin/mount /dev/sdb1 -o ro,noatime /media/sdb1 ) &amp;  and the resulting iteration.txt file has: before while iteration only. Which means the condition for the while loop is never triggered. This means the device node is available at time of execution, right? EDIT 2 I finally got it to work with the second answer here:  Adding PrivateMounts=No to the systemd-udevd.service worked for me.
I have the following content in in /etc/udev/rules.d/81-external-disk.rules:  ENV{ID_FS_UUID}=="6826692e-79f4-4423-8467-cef4d5e840c5", RUN{program}+="/bin/mount -o nofail,x-systemd.device-timeout=1 -t ext4 -U 6826692e-79f4-4423-8467-cef4d5e840c5 /backup/external"   After running:  udevadm control --reload ; udevadm trigger /dev/sdb1   It does nothing at all. However if II change the mount command for something such as /bin/touch /tmp/xyz it works.  Versions:  [root@helsinki rules.d]# rpm -qa | grep udev libgudev1-219-19.el7_2.12.x86_64 python-pyudev-0.15-7.el7_2.1.noarch [root@helsinki rules.d]# rpm -qa | grep systemd systemd-libs-219-19.el7_2.12.x86_64 systemd-219-19.el7_2.12.x86_64 systemd-sysv-219-19.el7_2.12.x86_64 [root@helsinki rules.d]# cat /etc/redhat-release  CentOS Linux release 7.2.1511 (Core)
Do Stack Exchange sites allow editing of comments and posts from other users? How to remove URI encoding from file names? I realise this might be quite a simple question, but I'm still quite new to the command line and only have a grasp of basic commands.  I've downloaded some lecture presentations (~25 or so) from my University however on doing so they've been named things like...  L2%20Development%20of%20immune%20system.pptx L4%20Molecular%20Recognition.pdf   As you can see they've downloaded with the URL encoding %20 instead of a space.  My question is how to batch rename all of these files so that the %20 is removed and replaced with a space instead? How to compare two columns and find differences in Excel? I have two columns in Excel that I want to compare and find the differences between them.  Suppose:   Col A has 50 numbers, i.e. 0511234567 Col B has 100 numbers in the same format Kinetic energy conservation in a collision Kinetic energy conservation in collision.  In any type of collision type of collision if we take the system to comprised of both bodies then the net external force is zero. So the work done by external force is also zero. By the relation $W=K_f-K_i$ as $W$ is zero hence kinetic energy is conserved. But this not the case.   Can you tell me what is the flaw in my argument? Some people say that the argument has neglected the fact that some kinetic energy is transformed into heat. But heat is created due to the interactions between bodies during collision which is thus an internal force and thus shouldn't affect kinetic energy. When is it appropriate to use the original pronunciation of a foreign word versus the English pronunciation? When reading to an audience, or speaking in conversation, when is it appropriate to use the original pronunciation of a foreign word versus the English pronunciation (assuming you know the appropriate pronunciation for it)? Is it considered rude, or condescending? 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If you are experiencing the &quot;low-graphics mode&quot; error when trying to login but none of the following answers work for you, please do ask a new question and then update the answers of this canonical question as and when your new question gets answered.   When I try to boot into my computer, I am getting this error:  The system is running in low-graphics mode Your screen, graphics cards, and input device settings could not be detected correctly. You will need to configure these yourself.   How do I fix the failsafe X mode and login into my computer?  Answer index: grep'ping files for multiple strings (not necessarily on the same line) The "correct" way to write a set without a specific element is as follows: $S \setminus \{s\}$  But in some contexts this is cumbersome to write/type or read, and it detracts from the flow of the writing. Is it acceptable to just use $S \setminus s$?  Edit: By "cumbersome" i mean they look bad when you're trying to inline formulas in LaTeX. On finding polynomials that approximate a function and its derivative (extensions of Stone-Weierstrass?) The Stone-Weierstrass Theorem tells us that we can approximate any continuous $f:\mathbb{R}^n\to\mathbb{R}$ arbitrary well on a compact subset of $\mathbb{R}^n$ by some polynomial. Suppose that $f$ is continuously differentiable, under what conditions can we guarantee we can find a polynomial $p$ such that $p$ approximates arbitrarily well $f$ and the partial derivatives approximate of $p$ arbitrarily well those of $f$ (on a compact subset of $\mathbb{R}^n$)? References are welcome. See below for my (probably naive) approach to the question.    It is straightforward to find conditions if $n=1$: Let $K:=[a,b]\subseteq\mathbb{R}$ and let $K_+$ denote some open cover of $K$. Suppose that $f:K_+\to\mathbb{R}$ is continuously differentiable and let $f'$ denote its derivative. 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