Bash login essentials: stuff I always add to my login scripts, but never had all in one place

dot-bashrc-essentials.sh

# .bashrc essentials
# copy and paste any parts that you need into your own ~/.bashrc

# you may get a nicer one by default from your *nix distro; uncomment this
# only if you have an ugly default "bash-x.y$" prompt string
#PROMPT="[\u@\h:\w]$ "

# trim the display of '\w' to just the last three path elements
PROMPT_DIRTRIM=3

# expand environment variables with tab completion if they would form part of
# a valid file/pathname (previously default behavior changed in Bash >=4.2)
# source: https://superuser.com/a/604757/73744
# assistance from: https://unix.stackexchange.com/a/498859/278323
shopt | grep -q '^direxpand\b' && shopt -s direxpand

# other useful options for 'cd'; uncomment if they seem appealing to you
# allow cd-ing to variable names WITHOUT the "$" (e.g., 'cd LABROOT')
#shopt -s cdable_vars
# allow minor speling mistakes in 'cd' commands
#shopt -s cdspell

# don't use Vim as a default editor
# (see also: https://stackoverflow.com/q/11828270)
export EDITOR=nano
export VISUAL=nano

# don't store commands in history if they're prefixed with a space; also keep
# only the most recent duplicate command; if you want to keep commands from
# being written to the history file, also try 'set +o history' (history
# recording is on by default in interactive shells)
export HISTCONTROL=ignorespace:erasedups
# older Bashes might need something like this
#export HISTIGNORE="[ \t]*:cd *:ls *:history *"

# sync history to disk immediately after every command; use 'history -n' to
# re-read history from a different Screen or tmux session
# source: https://unix.stackexchange.com/a/48113
HISTSIZE=100000          # how many commands to remember for current session
HISTFILESIZE=100000      # how many commands to keep in ~/.bash_history
HISTTIMEFORMAT='%F %T  ' # give each one a date/timestamp
shopt -s histappend      # append to history, don't overwrite

# append current history list to the history file after each command finishes
PROMPT_COMMAND="${PROMPT_COMMAND:+$PROMPT_COMMAND; }history -a"

# Allow 'less' to display colors and prevent clearing the screen when it quits:
export LESS=-RX

# If 'xclip' exists in the PATH, this is probably Linux, create more
# convenient aliases for manipulating the clipboard that work like
# 'pbcopy'/'pbpaste' (pasteboard copy/paste) on a Mac.
if [[ $(type -t xclip) == file ]]; then
    alias pbcopy='xclip -i -selection clipboard'
    alias pbpaste='xclip -o '
fi

# enable color support of ls and also add handy aliases
if [[ $TERM != dumb ]] && [[ -x /usr/bin/dircolors ]]; then
    eval "`dircolors -b`"  # might be done already in system-wide login script(s)
    alias ls='ls -F --color=auto'  # use 'ls -FG' instead on Darwin / macOS
    #alias dir='ls --color=auto --format=vertical'
    #alias vdir='ls --color=auto --format=long'

    alias grep='grep --color=auto'
    alias fgrep='fgrep --color=auto'
    alias egrep='egrep --color=auto'
fi

# prevent damaging mistakes by forcing 'rm' and others into "interactive" mode
# by default; use 'rm -f' or '\rm' to force normal (don't-ask) behavior
alias rm='rm -i'
alias mv='mv -i'
alias cp='cp -i'
alias ln='ln -i'

# a better 'which'; identifies *all* copies of a program in your PATH
# directories, aliases and shell functions, too
alias whence='type -a'

# ISO 8601 date; use like this: 'touch filename-$(isod)'
alias isod='date +%Y%m%d'
alias isodd='date +%Y-%m-%d'

# some helpful 'ls' aliases that are often present on Linux systems
alias ll='ls -l'
alias la='ls -A'
alias l='ls -CF'

##
##  other aliases you may be interested in (uncomment to enable them)
##
# disk usage by subdirectory; see also `du --max-depth` if on Linux
# Source: https://serverfault.com/a/76201
#alias dud='find . -maxdepth 1 -type d -print0 | xargs -0 du -sh | sort -rh'

# Like 'DIR /ad' on MS-DOS; just show directories
#alias lsd='find * -maxdepth 0 -type d | column'

# 'cd' into the most-recently-modified directory; normally you wouldn't want
# to parse 'ls' (http://mywiki.wooledge.org/ParsingLs), in this case it's OK
#alias cdlast='cd "$(
#  \ls -t \
#    | while read x; do if [[ -d $x ]]; then echo "$x"; break; fi; done )"'

##
##  third-party shell productivity utilities
##
# quickly 'j'ump to recently/frequently-used directories, with fuzzy matching
# please install fasd (https://github.com/clvv/fasd) and uncomment these
#eval "$(fasd --init auto)"
#alias j='fasd_cd -d'
#alias v='f -e vim' # quick opening files with vim
#_fasd_bash_hook_cmd_complete j v

# reformat input lines, rewrapping, preserving indents and comment characters
# please build and/or install Par (http://www.nicemice.net/par/) then
# uncomment this line
#export PARINIT='rTbgqR B=.,?_A_a Q=_s>|'

dot-inputrc

# a nice .inputrc
# source: http://robertmarkbramprogrammer.blogspot.com/2008/08/inputrc-for-bash-history-completion.html

# Include system wide settings which are ignored by default if one has their
# own .inputrc
$include /etc/inputrc

# By default up/down are bound to previous-history and next-history
# respectively. The following does the same but gives the extra functionality
# where if you type any text (or more accurately, if there is any text between
# the start of the line and the cursor), the subset of the history starting
# with that text is searched (like 4dos for e.g.).

# Note to get rid of a line just Ctrl-C
"\e[B": history-search-forward
"\e[A": history-search-backward

$if Bash
  # F10 toggles mc on and off
  # Note Ctrl-o toggles panes on and off in mc
  "\e[21~": "mc\C-M"

  # source: http://jesrui.sdf-eu.org/remember-all-your-bash-history-forever.html
  # delete last command from history
  #"\e\C-x": "history -d $((HISTCMD-2))"
  # delete second to last command from history
  #"\e\C-y": "history -d $((HISTCMD-3))"

  # do history expansion when space entered
  #Space: magic-space
$endif

# case-insensitive completion
set completion-ignore-case On

ssh-agent-start.sh

# Unlock SSH private key upon login and ensure that multiple login sessions
# don't start extra instances of the agent.
#
# Works great with Cygwin.
#
# source: https://help.github.com/articles/working-with-ssh-key-passphrases/
env=~/.ssh/agent.env

agent_load_env () {
    test -f "$env" && . "$env" >| /dev/null
}

agent_start () {
    (umask 077; ssh-agent >| "$env")
    . "$env" >| /dev/null
}

agent_load_env

# agent_run_state: 0=agent running w/ key; 1=agent w/o key; 2= agent not running
agent_run_state=$(ssh-add -l >| /dev/null 2>&1; echo $?)

if [ ! "$SSH_AUTH_SOCK" ] || [ $agent_run_state = 2 ]; then
    agent_start
    ssh-add
elif [ "$SSH_AUTH_SOCK" ] && [ $agent_run_state = 1 ]; then
    ssh-add
fi

unset env