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What is the point of “grep -q”

I was reading the grep man page and came across the -q option, which tells grep to “not write anything to standard output. Exit immediately with zero status if any match is found, even if an error was detected.” I don’t understand why this could be desirable or useful behavior. In a program …

How to send actions directly to input event?

I have a touch screen with events at /dev/input/event12 and /dev/input/event13. /dev/input/event12 is the main touch input, and in essence, I’d like to send instructions to the event directly to control behavior (ie, click location etc). Tools like xdotool do not want to work because this device is bein…

How to make command “Hadoop” work in linux 18.04?

I installed Hadoop and now it works with command /usr/local/hadoop/bin/hadoop. Where and how should I add this path to make command hadoop work without a full path to file? I already tried .bashrc and /etc/environment, but it didn’t help. Answer You need to add it to your PATH environment variable. PATH…

What does this strange construction “{} ;” means?

Why do we use this strange construction {} ; in linux terminal for exec command? For example, Answer Looking for info I found this post in AskUbuntu which I think is family from StackOverflow where an User ask the same as you. Link Hope It is useful.

loop to test all NFS mount point

this code work very well If I try to put it into a loop for : Aim is to test all mounts points, this code test and read only the first entries from nfs_array. If I swapped testnfs1 with testnfs2 this code will test testnfs2 mount point and forget testnfs1 🙁 Answer In your loop it should be: Currently it&#8217…