[GRLUG] Custom $PS1 settings

[Rick Vargo]

Some of you guys need to get outside more.  See the sun!  Bunch of
geeks!  :)  J/K

Rick


Raymond McLaughlin wrote:
> Michael Mol wrote:
>   
>> Like, I suspect, many people, I have custom settings for PS1 in my
>> ~/.bashrc file:
>>
>> PS1="\u@\H\w\n\t \$ "
>>
>> This give me a conventient prompt:
>>
>> shortcircuit at caterpillar~
>> 22:53:34 $
>>
>> I see my username, the name of the machine I'm logged into, my path,
>> the current time, and whether or not I'm logged in as root.
>>
>> In the past, I've had prompts which executed scripts that displayed an
>> indicator to tell me whether or not certain accounts were logged in.
>>
>> What do you use for a prompt?  What's the most unique prompt you've ever used?
>>     
>
> Glad you asked, this is one of my favorite hacks. Most people know about
> the $PS1 variable, but few know about the $PROMPT_COMMAND variable.
> Where $PS1 defines how the prompt line looks, $PROMPT_COMMAND can define
> a script to be run immediately before the command prompt is displayed.
>
> In my case $PROMPT_COMMAND=prompt_command where 'prompt_command' is a
> function defined in a startup script named .prompt_command which is in
> turned called from a line in .bashrc (test -s ~/.prompt_command && .
> ~/.prompt_command). In addition to setting $PS1 to show which device has
> the current console, it defines a function prompt_command to write
> $USERNAME@$HOST:$PWD , in colored text on contrasting background, at the
> top right corner of the display.
>
> below is my startup script .prompt_command. I have been tweeking it for
> a couple years. Note that I pasted it as a quotation to guard against
> line wrap mangling. Each line begins with a leading '>' that should not
> be included in the actual script.
>
>   
>> # bash recognizess a variable called PROMPT_COMMAND and, if it is set,
>> # executes whatever it evaluates to. This script needs to be called from .bashrc.
>> # The first part defines a function, 'prompt_command', which evaluates
>> # the current working and directory, (and hostname and username if desired), 
>> # then writes it to the upper right corner of the display in contrasting color.
>> # The variable PROMPT_COMMAND is then set equal to 'prompt_command'.
>> # The second part provides a short prompt string indicating the current input device.
>>
>> ##############################
>> # Step 1: Define function.
>> ##############################
>> function prompt_command 
>> {
>> tput sc   # Save the current cursor position
>>
>> # set background, forground color, bold
>> if [ $UID = 0 ]
>>   then tput setab 1 ; tput setaf 3 ; tput bold  # yellow text on red background for root
>>   else tput setab 4 ; tput setaf 6 ; tput bold  # cyan text on blue background for users
>> fi
>>
>> # Define DIR as current directory, with current users home reduced to ~
>> DIR=$(pwd | sed s?$(echo ~)?~?)
>>
>> # OLDDIR is directory string most recently WRITTEN TO THE SCREEN.
>> # If $OLDDIR longer than the current $DIR it will be necessary to clean up artifacts,
>> # which might remain to the left of the new one, by over-writing with blank spaces.
>> if [ -z $OLDDIR  ]; then OLDDIR=$DIR; fi # $OLDDIR must not be empty.
>> DIFF=$(($(echo $OLDDIR | wc -m)-$(echo $DIR | wc -m)))
>>
>> ## Define SPLASH_STRING - pick one
>> # SPLASH_STRING="$DIR"
>> # SPLASH_STRING="$HOSTNAME:$DIR"
>> user=$(echo ~ | sed s?/home?? |sed s?/??)
>>
>> SPLASH_STRING="$user@$HOSTNAME:$DIR"
>>
>> # Define pad as the total width of the terminal less the length
>> # of the splash string
>>  
>> if [ $DIFF -gt 0 ];
>>   then
>>     let pad=$(tput cols)-$(echo $SPLASH_STRING | wc -m)-$DIFF+1
>>     tput cup 0 $pad  # position the cursor so that the hostname and PWD are at top left (Y=0, X=$pad)
>>     while [ $DIFF -gt 0 ]; do echo -n " "; DIFF=$(($DIFF-1));done
>>
>>   else
>>     let pad=$(tput cols)-$(echo $SPLASH_STRING | wc -m)+1
>>     tput cup 0 $pad  # position the cursor so that the hostname and PWD are at top left (Y=0, X=$pad)
>> fi
>>
>> echo -n "$SPLASH_STRING"   #Show the hostname and present working directory.
>>
>> OLDDIR=$DIR   # Save directory string for DIFF in next execution.
>> tput rc   # Return the cursor to the saved position
>> }
>>
>> ########################################
>> # Step 2: Set variable equal to function
>> ########################################
>> PROMPT_COMMAND=prompt_command
>>
>> ############################################################
>> # Step 3: Set prompt string to display current input device
>> ############################################################
>>
>> #Evaluate current logged device from output of 'tty'
>> tty=$(echo $(tty) |sed s%/dev/%%)
>>
>> # Set command prompt to show current console
>> PS1="$tty \\$ "
>>     
>
>
>
> _______________________________________________
> grlug mailing list
> grlug at grlug.org
> http://shinobu.grlug.org/cgi-bin/mailman/listinfo/grlug
>