kostoglotov stephen-hannam

Isolate CPU cores

A script to Isolate Cores from the linux kernel, with an option to generate an undo script.

#!/bin/bash
# - disables the Linux realtime throttling which ensures that realtime processes cannot starve the CPUS.
# - disables the Linux watchdog timer which is used to detect and recover from software faults.
# - disables the debugging feature for catching hardware hangings.
# - sets the default CPU affinity of 0b11 (3), which means that only CPU 0 and 1 handle interrupts.
# - moves all interrupts off cpus specified below starting at 2 and above.

Template: Recursive Calls if fork returns positive value

#include <sched.h>
#define errExit(msg)    do { perror(msg); exit(EXIT_FAILURE); \
                        } while (0)
                        
cpu_set_t set;
CPU_ZERO(&set);

Procedural Privilege Escalation (from LFS scripts)

as_root()
{
  if   [ $EUID = 0 ];        then $*
  elif [ -x /usr/bin/sudo ]; then sudo $*
  else                            su -c \\"$*\\"
  fi
}

Instructions

Create two network namespaces

ip netns add ns0
ip netns add ns1

Assign interfaces to namespaces

UNIX Box Chars Like a Scamp

#!/bin/bash

on='\x1b(0' # Esc ( 0
off='\x1b(B' # Esc ( B

for i in 6a 6b 6c 6d 6e 71 74 75 76 77 78; do
  printf "0x$i \x$i $on\x$i$off\n"

done

Dockery do

remove all containers

$docker rm $(docker ps -a -q)

remove all images

$docker rmi $(docker images -q)

remove all images forcefully

$docker rmi $(docker images -q) --force

Filter Log as it's Written and Append Timestamp

tail -f afile.log | egrep -i --line-buffered 'matching|filter|terms' | awk '{ printf strftime("%c") "\n" $0}'

Bla bla ¹

more bla blah

Ampersand: & &

a_b, a_b

*** represents a user defined substring

.
├── C
│   ├── ***_handling/