If you like using the console, try this in your bash_profile (or equivalent):
export PS1="\\$(if [[ \\$? == 0 ]]; then echo \"\\[\\033[01;32m\\]?? \"; else echo \"\\[\\033[01;31m\\]?? (\\$?)\"; fi)\\[\\033[01;34m\\] [\\W]\\[\\033[01;00m\\]: "After you execute a command, the next prompt will be preceded by ?? to show that it was successful, or ?? and the error number to show a problem. The output will look something like this:
?? [~]: tme
-bash: tme: command not found
?? (1) [~]: time
real 0m0.000s
user 0m0.000s
sys 0m0.000s
?? [~]:I actually use smiley face/mad face, but the forum won’t let me show that. 