Add the following to ~/.bashrc then reload config or reopen terminal.

### Terminal Syntax Highlighting

# Setup: "apt-get install highlight"

# Pipe Highlight to less (remove --line-numbers option for better copy&pasting)
export LESSOPEN="| $(which highlight) %s --out-format xterm256 --line-numbers --quiet --force --style freya"
export LESS=" -R"
# remove -N and --line-numbers for better copy&pasting. other options can be defined like this:
alias less='less -m -N -g -i -J --line-numbers --underline-special'
alias more='less'

# Use "highlight" in place of "cat"
alias cat="highlight $1 --out-format xterm256 --line-numbers --quiet --force --style freya"

# Setup JSON Syntax Highlighting
# Copy js.lang to json.lang with the following command
# cp "$(dirname $(brew list highlight | head -n 1))/share/highlight/langDefs/js.lang" "$(dirname $(brew list highlight | head -n 1))/share/highlight/langDefs/json.lang"

Source: https://gist.github.com/textarcana/4611277

On dark terminal, the following themes work well:
bluegreen
ekvoli
freya
moria
solarized-light

To only allow ansi control characters of text files, add to .bashrc

export LESS=" -R"