12.6. Prompt Depending on Connection Type

Bradley M Alexander (storm@tux.org) had the excellent idea of reminding his users what kind of connection they were using to his machine(s), so he colour-codes prompts dependent on connection type. Here's the bashrc he supplied to me:


# /etc/bashrc

# System wide functions and aliases
# Environment stuff goes in /etc/profile

# For some unknown reason bash refuses to inherit
# PS1 in some circumstances that I can't figure out.
# Putting PS1 here ensures that it gets loaded every time.

# Set up prompts. Color code them for logins. Red for root, white for 
# user logins, green for ssh sessions, cyan for telnet,
# magenta with red "(ssh)" for ssh + su, magenta for telnet.
THIS_TTY=tty`ps aux | grep $$ | grep bash | awk '{ print $7 }'`
SESS_SRC=`who | grep $THIS_TTY | awk '{ print $6 }'`

SSH_FLAG=0
SSH_IP=`echo $SSH_CLIENT | awk '{ print $1 }'`
if [ $SSH_IP ] ; then
  SSH_FLAG=1
fi
SSH2_IP=`echo $SSH2_CLIENT | awk '{ print $1 }'`
if [ $SSH2_IP ] ; then
  SSH_FLAG=1
fi
if [ $SSH_FLAG -eq 1 ] ; then
  CONN=ssh
elif [ -z $SESS_SRC ] ; then
  CONN=lcl
elif [ $SESS_SRC = "(:0.0)" -o $SESS_SRC = "" ] ; then
  CONN=lcl
else
  CONN=tel
fi

# Okay...Now who we be?
if [ `/usr/bin/whoami` = "root" ] ; then
  USR=priv
else
  USR=nopriv
fi

#Set some prompts...
if [ $CONN = lcl -a $USR = nopriv ] ; then
  PS1="[\u \W]\\$ "
elif [ $CONN = lcl -a $USR = priv ] ; then
  PS1="\[\033[01;31m\][\w]\\$\[\033[00m\] "
elif [ $CONN = tel -a $USR = nopriv ] ; then
  PS1="\[\033[01;34m\][\u@\h \W]\\$\[\033[00m\] "
elif [ $CONN = tel -a $USR = priv ] ; then
  PS1="\[\033[01;30;45m\][\u@\h \W]\\$\[\033[00m\] "
elif [ $CONN = ssh -a $USR = nopriv ] ; then
  PS1="\[\033[01;32m\][\u@\h \W]\\$\[\033[00m\] "
elif [ $CONN = ssh -a $USR = priv ] ; then
  PS1="\[\033[01;35m\][\u@\h \W]\\$\[\033[00m\] "
fi

# PS1="[\u@\h \W]\\$ "
export PS1
alias which="type -path"
alias dir="ls -lF --color"
alias dirs="ls -lFS --color"
alias h=history