Bash

I like the default way things work in Debian, but I have a couple of modifications:

# don't put duplicate lines in the history
export HISTCONTROL=ignoredups
 
# enable color support of ls and also add handy aliases
if [ "$TERM" != "dumb" ]; then
    eval "`dircolors -b`"
    alias ls='ls --almost-all --color=auto'
    alias vls='ls --almost-all --color=auto --format=vertical'
    alias ll='ls --almost-all --color=auto --format=long --human-readable'
    # also colorize grep
    alias grep='grep --color=auto'
fi