Make OS X Terminal commands I type BOLD

Edit your ~/.bash_profile or ~/.bashrc (see Gilles' comment below) and add the following lines:

BOLD="\[\033[1m\]"
OFF="\[\033[m\]"
PS1="${OFF}\u@\h:\w \$${BOLD}"
PS2="> ${BOLD}"
trap 'echo -ne "${OFF}" > $(tty)' DEBUG

Move the ${BOLD} around to make part of the prompt also bold. If the prompt itself should not be colored, you need the ${OFF} prefix in PS1, otherwise empty lines (pressing enter without having something written) will make the following prompt bold (credits to @Jay, thanks again!)

This adds a debug trap to turn bold format off, so it's quite a hack. Credits (works without group tty on OS X though).

This is a bit of a hack, so use it at your own risk.

Only setting your PS1/PS2 prompts to bold would be easier and just as visible:

BOLD="\[\033[1m\]"
OFF="\[\033[m\]"
PS1="${BOLD}\u@\h:\w \$${OFF}"
PS2="${BOLD}>${OFF} "

I had a little trouble with the solutions here while using El Capitan (esp. in iTerm2 but in plain old Terminal as well). I got two sorts of errors:

1. The ability to delete my bash prompt entirely by just pressing space then backspace

2. Unwanted characters finding their way into my bash output, e.g. the input pwd would result in

   \[\]/Users/home/Directory
   

   or in

   \e[0m/Users/home/Directory
   

I propose the following solution, which is really just more of the same.

    BOLD="\033[1m"
    OFF="\033[m"
    PS1="${OFF}\u@\h :${BOLD}"
    PS2="> ${BOLD}"
    trap 'echo -ne "${OFF}" > $(tty)' DEBUG