bkw777

It's common these days to need to replace obsolete DIP chip parts in vintage electronics with small PCBs that fit where the DIP chips used to go. For instance the infamous SID and PLA chips in Commodore computers.

However the most common types of pin headers available to make the legs are actually too thick and they damage DIP sockets. This includes common machined round pins, which are thinner than the square pins, and ok for use in round sockets, but still technically a bit too thick for leaf sockets. They can compress the wipers and make the socket no longer make a good connection with a real DIP chip any more. Also those pins always have a quite large insulator & shoulder, and in some cases there is not much room where a DIP chip came out of for that much vertical thickness of the pin header shoulders and insulators plus the pcb plus the components soldered to the pcb.

Here are 3 different ways to make DIP legs on PCBs, where the legs are thin enough not to stretch out leaf/wiper style DIP sockets, and

bkw777

#!/usr/bin/env bash
# Example to detect OS in bash using bash built-in variable $OSTYPE instead of `uname`

# platform differences 
stty_f="-F" SERIAL_TTY_PREFIX=ttyUSB # Default (Linux)
case "${OSTYPE,,}" in
	*bsd*) stty_f="-f" SERIAL_TTY_PREFIX=ttyU ;; # FreeBSD/NetBSD/OpenBSD/etc
	darwin*) stty_f="-f" SERIAL_TTY_PREFIX=cu.usbserial- ;; # Mac OSX
esac

bkw777

#!/usr/bin/env bash
# file-to-ram, ram-to-file, in pure bash
# binary-safe including nulls, no external tools, no sub-shells
# Brian K. White [email protected]

# read file binary to h[] hex pairs
ftoh () {
  local -i i= ;local x= LANG=C ;h=()
  while IFS= read -d '' -r -n 1 x ;do printf -v h[i++] '%02X' "'$x" ;done <$1
}

bkw777

#!/usr/bin/env bash
# Read binary data, including null bytes, from a serial port,
# in pure bash with no external executables nor even subshells,
# even though it's not possible to store a null in a shell variable.
# Uses globals to avoid forking subshells.

# Example, echo -e "\0\0\0" |read FOO  or  printf -v FOO '%b' "\0\0\0"
# FOO will not contain any 0x00 bytes.
# Same goes for mapfile/readarray.

bkw777

#!/usr/bin/env bash
# sleep without externals or children
# and without the bash sleep builtin

# mkfifo is not exactly free, but you only do this part once.
# After that it is relatively free to call _sleep all you want even in tight loops.
sleep_fifo=/tmp/.${0//\//_}.$$.sleep.fifo
trap "rm -f $sleep_fifo" EXIT
mkfifo $sleep_fifo || { echo "$0: Error creating sleep fifo \"$sleep_fifo\"" >&2 ; exit 1 ; }
exec 9<>$sleep_fifo

bkw777

#!/bin/bash
# urlencode / urldecode in pure bash without externals
# no backticks or forking, all in-memory ops
# urlencode/urldecode the contents of $x, place results back in $x
# allow bash-isms
# [email protected]

urlencx () {
  local LANG=C i b t=$x l=${#x} ;x=''
  for ((i=0;i<l;i++)); do

bkw777

#!/bin/bash
# create an exclusive temp dir
# allow bash-isms
# [email protected]

# If you don't need to retain the temp files after execution, and you reliably
# clean up on exit with a trap, and you only need to worry about concurrent
# instances, then you can just use $$ cheaper instead of this "until mkdir" loop.

# Comment this out to retain the temp files after execution (logging, debugging)

bkw777

#!/usr/bin/env bash
# HTTP web service implemented in socat + bash
# Usage: socat -T 1 -d -d tcp-l:8080,reuseaddr,fork,crlf exec:./http_server.sh
# Purpose: Provide an HTTP server that displays the current server date,
# to validate the artifact structure and play with it.
# Note: socat crlf option is translating all our \n to \r\n on output.

http_version="1.0"

declare -a _http_responses=(