grep --color
I use grep a lot. Today I realized that others might not know that GNU grep can highlight matches, or how to combine it with less. So here's part of my Bash config, and some examples uses:
alias grep='grep --color=auto'
alias egrep='egrep --color=auto'
function legrep {
egrep --color=yes "$@" | less -R
}
$ legrep '[Gg]nome' */*.xml $ legrep -i foo /usr/share/dict/words $ grep bar | egrep -v 'baz|qux' | legrep bar
