Delete duplicate lines pairwise?
I encountered this use case today. It seems simple at first glance, but fiddling around with sort, uniq, sed and awk revealed that it’s nontrivial.
Unix & Linux
Do the virtual address spaces of all the processes have the same content in their “Kernel” parts?
The Linux Programming Interface shows the layout of a virtual address space of a process:
comparing the first column of two files and printing the entire row of the second file if the first columns match
I have two files in these formats:
Why is there no apparent clone or fork in simple bash command and how it’s done?
Consider the following (with sh being /bin/dash):
Why doesn’t cp have a progress bar like wget?
Please note that I don’t ask how. I already know options like pv and rsync -P.
What is the difference between ping -w and ping -W?
What is the -w (deadline) flag in ping for? I cannot find a description of it in the ping man page; only for -W, which takes seconds as a parameter. What is the difference between them, and how can I set a ping timeout (if host is not responding) to 200ms?
renaming images to include creation date in name
When I look at the properties of an image, I can see the date the photo was taken in “Date Taken”. When I edit the images (proprietary program) this data gets lost.
Remapping both Caps Lock and Shift+Caps Lock in xkb
I am trying to configure xkb such that Caps Lock is mapped to the Compose key and Shift+Caps Lock functions as the traditional Caps Lock. I put the following in a new file called /usr/share/X11/xkb/symbols/gdwatson:
Obtaining PID of command earlier in Pipeline
I’m writing a bash script to use inotifywait to monitor a directory and kick off actions when changes are detected. Something like:
Print pids and names of processes as they are created
From the question here, the OP wants to repeatedly poll the pid of a process using pidof in a shell script. Of course this is inefficient as a new process must be started for the pidof program multiple times per second (I don’t know that this is the cause of the CPU spikes in the question, but it seems likely).