Playing with my Prompt

Posted by Fred Jean on October 19th, 2006 in Uncategorized

Up until a few days ago, I saw no reasons to change the shell prompt on my systems. It all looked a little different, but I was ok with it. Well, that changed last night while I attended a presentation at the Boulder-Denver Ruby Users Group. Ara, the presenter, had modified his prompt to show whether the previous command had succeeded or not. I decided to do the same to my systems. I came up with the following code added to my .bash_profile (with a lot of help from the Bash Prompt Howto) :

function my_prompt() {

   # Determines whether the previous command succeeded...

   if [ $? -eq 0 ]; then

      result="1;32m:)"

   else

      result="1;31m:("

fi

   pwd_length=20

   DIR=`pwd`

   echo $DIR | grep "^$HOME" >> /dev/null

   if [ $? -eq 0 ]

   then<

      CURRDIR=`echo $DIR | awk -F$HOME '{print $2}'`

      newPWD="~$CURRDIR"

      if [ $(echo -n $newPWD | wc -c | tr -d " ") -gt $pwd_length ]

      then

         newPWD="~/..$(echo -n $PWD | sed -e "s/.*\(.\{$pwd_length\}\)/\1/")"

fi

   elif [ "$DIR" = "$HOME" ]

   then

      newPWD="~"

   elif [ $(echo -n $PWD | wc -c | tr -d " ") -gt $pwd_length ]

   then

      newPWD="..$(echo -n $PWD | sed -e "s/.*\(.\{$pwd_length\}\)/\1/")"

   else

      newPWD="$(echo -n $PWD)"

fi

export PROMPT_COMMAND=my_prompt

PS1='33[1;30m\[33]2;\u@\h:${newPWD}\a\]\

[\u@\h ${newPWD}]\n33[${result} 33[1;30m\$ 33[0;39m'

As a result, this is what I now see in my terminal windows when things go well:

[fjean@voyager ~]:) $

And when things go bad:

[fjean@voyager ~/..ojects/yagrails-test]:( $

I have configured my work system and my PowerBook to use the new prompt. I have also added a few other tricks to my work desktop (such as setting the terminal window's title based on where I am in my file system).

Note: I did try to convey the colors, but it appears that Ecto and WordPress conspired to strip them away… I'll keep trying though…