TIL Ctrl-R trick of using history in Linux How to use the history command in Linux. history -d <line number> removes a line from history and history -c clears history. !sudo searches in history last command starting from “sudo” and reruns it, while !sudo:p just displays found command without running it. !?echo searching and runs last command having substring “echo”.

TIL what is OpenMP.

OpenMP (Open Multi-Processing) is an application programming interface (API) that supports multi-platform shared-memory multiprocessing programming in C, C++, and Fortran, on many platforms, instruction-set architectures and operating systems, including Solaris, AIX, FreeBSD, HP-UX, Linux, macOS, and Windows. It consists of a set of compiler directives, library routines, and environment variables that influence run-time behavior.

TIL what is Proportional control in engineering and process control. Not really learned. Every engineer intuitively understands and uses proportional control not knowing how it’s called.

Proportional control is a type of linear feedback control system in which a correction is applied to the controlled variable, and the size of the correction is proportional to the difference between the desired value (setpoint, SP) and the measured value (process variable, PV).

Read How to Make Sense of Distributed Processing With Python Daemons.