Skip to content

Tag: linux

Linux rename s/ – regex for wildcard single characte r

I have found a simple solution to my actual requirement, but I would still like to understand how to use the regex equivalent of the single character wildcard ? which we use for filtering … in say ls I would like to rename a group of files which differ by one character. FROM TO As I said above, my simpl…

Futex and pthreads issue

I’m testing futexes with pthreads. I’ve written following program: And sometimes it returns 0 as a sum which is proper value but sometimes the returned value of sum is different than 0. My question is why the returned values of “sum” are different than 0? I suspect that there is someth…

trying to cause SIGSEGV in mmap

I’m trying to create a memory mapping of length greater than the underlying file. When I access pages of the mapping (which are not correspondingly mapped to a file), a SIGBUS is caused. However when I try to access the memory outside the memory mapping length, it should cause SIGSEGV (but isn’t),…

Bash – format .txt file into pover pivot form

txt file called without_Commas.txt. The content looks like this: I need to format this data to look like this: Is there a way to do this? Kind Regards Elias Answer On each line, this loops over all the field numbers starting with the third field. Then it prints the first field ($1) followed by the current fie…

delete all files except a pattern list file

I need to delete all the files in the current directory except a list of patterns that are described in a whitelist file (delete_whitelist.txt) like this: How can I perform this in one bash line? Answer Any bash script can fit on one line: Check the output and then, if it’s OK: