Essential Linux config file additions that should be the default

.bashrc

# Eternal bash history.
# ---------------------
# Undocumented feature which sets the size to "unlimited".
# http://stackoverflow.com/questions/9457233/unlimited-bash-history
export HISTFILESIZE=
export HISTSIZE=
export HISTTIMEFORMAT="[%F %T] "
# Change the file location because certain bash sessions truncate .bash_history file upon close.
# http://superuser.com/questions/575479/bash-history-truncated-to-500-lines-on-each-login
export HISTFILE=~/.bash_eternal_history
# Force prompt to write history after every command.
# http://superuser.com/questions/20900/bash-history-loss
PROMPT_COMMAND="history -a; $PROMPT_COMMAND"
# Disable flow control so Ctrl-s doesn't freeze the terminal
stty -ixon

.inputrc

set completion-ignore-case on
set show-all-if-ambiguous on

.ssh\config

# Share a single TCP connection for multiple SSH instances to the same server
ControlMaster auto
ControlPath ~/.ssh/socket-%r@%h-%p
# Keep TCP connections alive after SSH exits so the next connection is fast
ControlPersist 604800

nice bash script header

#!/bin/bash
cd "${0%/*}" # cd to directory containing this script
# Print time taken on exit.
export START=`date +%s`
trap 'EXIT_CODE=$?; set +ex; echo; echo Took $((`date +%s`-START)) second\(s\).; if [ $EXIT_CODE -ne 0 ]; then echo -e "\n---- ERROR ----\n"; fi' EXIT
# Echo all commands before execution and exit if any fail.
set -ex

script that kills all children on exit

#!/bin/bash
# Respond to SIGTERM by killing all child processes.
if [ "$1" != "--is-child" ]; then
  set -m; "$0" --is-child "$*" & PGID=$(ps -p $! -o pgid=)
  trap "exit" INT TERM;trap "pkill -g $PGID" EXIT;wait;exit
fi
shift

single instance bash script header

#!/bin/bash
# Kill all other invocations of this script (and all their child processes)
# before starting. In order for this to work some hacks are needed. First,
# to uniquely identify this script, always invoke it with its exact full path
# according to realpath. Second, find other instances using pidof. Third,
# list all descendants of those processes and kill them all with SIGINT.
# Finally, we can continue into the real script below.
if [ "$0" != "$(realpath "$0")" ]; then "$(realpath "$0")" "$@"; exit; fi
descendants () {
  local children=$(ps -o pid= --ppid "$1")
  for pid in $children; do descendants "$pid"; done
  echo "$children"
}
for pid in $(pidof -x "$0" -o $$); do kill -2 $pid $(descendants $pid); done