Advanced Bash-Scripting Guide:

Appendix L. Sample .bashrc and .bash_profile Files

The ~/.bashrc file determines the behavior of interactive shells. A good look at this file can lead to a better understanding of Bash.

Emmanuel Rouat contributed the following very elaborate .bashrc file, written for a Linux system. He welcomes reader feedback on it.

Study the file carefully, and feel free to reuse code snippets and functions from it in your own .bashrc file or even in your scripts.

Example L-1. Sample .bashrc file

#============================================================= # # PERSONAL $HOME/.bashrc FILE for bash-3.0 (or later) # By Emmanuel Rouat <no-email> # # Last modified: Sun Nov 30 16:27:45 CET 2008 # This file is read (normally) by interactive shells only. # Here is the place to define your aliases, functions and # other interactive features like your prompt. # # The majority of the code here assumes you are on a GNU # system (most likely a Linux box) and is based on code found # on Usenet or internet. See for instance: # # http://tldp.org/LDP/abs/html/index.html # http://www.caliban.org/bash/ # http://www.shelldorado.com/scripts/categories.html # http://www.dotfiles.org/ # # This bashrc file is a bit overcrowded -- remember it is just # just an example. Tailor it to your needs. # # #============================================================= # --> Comments added by HOWTO author. #------------------------------------------------------------- # Source global definitions (if any) #------------------------------------------------------------- if [ -f /etc/bashrc ]; then . /etc/bashrc # --> Read /etc/bashrc, if present. fi #------------------------------------------------------------- # Automatic setting of $DISPLAY (if not set already). # This works for linux - your mileage may vary. ... # The problem is that different types of terminals give # different answers to 'who am i' (rxvt in particular can be # troublesome). # I have not found a 'universal' method yet. #------------------------------------------------------------- function get_xserver () { case $TERM in xterm ) XSERVER=$(who am i | awk '{print $NF}' | tr -d ')''(' ) # Ane-Pieter Wieringa suggests the following alternative: # I_AM=$(who am i) # SERVER=${I_AM#*(} # SERVER=${SERVER%*)} XSERVER=${XSERVER%%:*} ;; aterm | rxvt) # Find some code that works here. ... ;; esac } if [ -z ${DISPLAY:=""} ]; then get_xserver if [[ -z ${XSERVER} || ${XSERVER} == $(hostname) || \ ${XSERVER} == "unix" ]]; then DISPLAY=":0.0" # Display on local host. else DISPLAY=${XSERVER}:0.0 # Display on remote host. fi fi export DISPLAY #------------------------------------------------------------- # Some settings #------------------------------------------------------------- ulimit -S -c 0 # Don't want any coredumps. set -o notify set -o noclobber set -o ignoreeof set -o nounset #set -o xtrace # Useful for debuging. # Enable options: shopt -s cdspell shopt -s cdable_vars shopt -s checkhash shopt -s checkwinsize shopt -s sourcepath shopt -s no_empty_cmd_completion shopt -s cmdhist shopt -s histappend histreedit histverify shopt -s extglob # Necessary for programmable completion. # Disable options: shopt -u mailwarn unset MAILCHECK # Don't want my shell to warn me of incoming mail. export TIMEFORMAT=$'\nreal %3R\tuser %3U\tsys %3S\tpcpu %P\n' export HISTTIMEFORMAT="%H:%M > " export HISTIGNORE="&:bg:fg:ll:h" export HOSTFILE=$HOME/.hosts # Put list of remote hosts in ~/.hosts ... #------------------------------------------------------------- # Greeting, motd etc... #------------------------------------------------------------- # Define some colors first: red='\e[0;31m' RED='\e[1;31m' blue='\e[0;34m' BLUE='\e[1;34m' cyan='\e[0;36m' CYAN='\e[1;36m' NC='\e[0m' # No Color # --> Nice. Has the same effect as using "ansi.sys" in DOS. # Looks best on a terminal with black background..... echo -e "${CYAN}This is BASH ${RED}${BASH_VERSION%.*}\ ${CYAN} - DISPLAY on ${RED}$DISPLAY${NC}\n" date if [ -x /usr/games/fortune ]; then /usr/games/fortune -s # Makes our day a bit more fun.... :-) fi function _exit() # Function to run upon exit of shell. { echo -e "${RED}Hasta la vista, baby${NC}" } trap _exit EXIT #------------------------------------------------------------- # Shell Prompt #------------------------------------------------------------- if [[ "${DISPLAY%%:0*}" != "" ]]; then HILIT=${red} # remote machine: prompt will be partly red else HILIT=${cyan} # local machine: prompt will be partly cyan fi # --> Replace instances of \W with \w in prompt functions below #+ --> to get display of full path name. function fastprompt() { unset PROMPT_COMMAND case $TERM in *term | rxvt ) PS1="${HILIT}[\h]$NC \W > \[\033]0;\${TERM} [\u@\h] \w\007\]" ;; linux ) PS1="${HILIT}[\h]$NC \W > " ;; *) PS1="[\h] \W > " ;; esac } _powerprompt() { LOAD=$(uptime|sed -e "s/.*: \([^,]*\).*/\1/" -e "s/ //g") } function powerprompt() { PROMPT_COMMAND=_powerprompt case $TERM in *term | rxvt ) PS1="${HILIT}[\A - \$LOAD]$NC\n[\u@\h \#] \W > \ \[\033]0;\${TERM} [\u@\h] \w\007\]" ;; linux ) PS1="${HILIT}[\A - \$LOAD]$NC\n[\u@\h \#] \W > " ;; * ) PS1="[\A - \$LOAD]\n[\u@\h \#] \W > " ;; esac } powerprompt # This is the default prompt -- might be slow. # If too slow, use fastprompt instead. ... #=============================================================== # # ALIASES AND FUNCTIONS # # Arguably, some functions defined here are quite big. # If you want to make this file smaller, these functions can # be converted into scripts and removed from here. # # Many functions were taken (almost) straight from the bash-2.04 # examples. # #=============================================================== #------------------- # Personnal Aliases #------------------- alias rm='rm -i' alias cp='cp -i' alias mv='mv -i' # -> Prevents accidentally clobbering files. alias mkdir='mkdir -p' alias h='history' alias j='jobs -l' alias which='type -a' alias ..='cd ..' alias path='echo -e ${PATH//:/\\n}' alias libpath='echo -e ${LD_LIBRARY_PATH//:/\\n}' alias print='/usr/bin/lp -o nobanner -d $LPDEST' # Assumes LPDEST is defined (default printer) alias pjet='enscript -h -G -fCourier9 -d $LPDEST' # Pretty-print using enscript alias du='du -kh' # Makes a more readable output. alias df='df -kTh' #------------------------------------------------------------- # The 'ls' family (this assumes you use a recent GNU ls) #------------------------------------------------------------- alias ll="ls -l --group-directories-first" alias ls='ls -hF --color' # add colors for filetype recognition alias la='ls -Al' # show hidden files alias lx='ls -lXB' # sort by extension alias lk='ls -lSr' # sort by size, biggest last alias lc='ls -ltcr' # sort by and show change time, most recent last alias lu='ls -ltur' # sort by and show access time, most recent last alias lt='ls -ltr' # sort by date, most recent last alias lm='ls -al |more' # pipe through 'more' alias lr='ls -lR' # recursive ls alias tree='tree -Csu' # nice alternative to 'recursive ls' # If your version of 'ls' doesn't support --group-directories-first try this: # function ll(){ ls -l "$@"| egrep "^d" ; ls -lXB "$@" 2>&-| \ # egrep -v "^d|total "; } #------------------------------------------------------------- # tailoring 'less' #------------------------------------------------------------- alias more='less' export PAGER=less export LESSCHARSET='latin1' export LESSOPEN='|/usr/bin/lesspipe.sh %s 2>&-' # Use this if lesspipe.sh exists export LESS='-i -N -w -z-4 -g -e -M -X -F -R -P%t?f%f \ :stdin .?pb%pb\%:?lbLine %lb:?bbByte %bb:-...' #------------------------------------------------------------- # spelling typos - highly personnal and keyboard-dependent :-) #------------------------------------------------------------- alias xs='cd' alias vf='cd' alias moer='more' alias moew='more' alias kk='ll' #------------------------------------------------------------- # A few fun ones #------------------------------------------------------------- function xtitle() # Adds some text in the terminal frame. { case "$TERM" in *term | rxvt) echo -n -e "\033]0;$*\007" ;; *) ;; esac } # aliases that use xtitle alias top='xtitle Processes on $HOST && top' alias make='xtitle Making $(basename $PWD) ; make' alias ncftp="xtitle ncFTP ; ncftp" # .. and functions function man() { for i ; do xtitle The $(basename $1|tr -d .[:digit:]) manual command man -F -a "$i" done } #------------------------------------------------------------- # Make the following commands run in background automatically: #------------------------------------------------------------- function te() # Wrapper around xemacs/gnuserv ... { if [ "$(gnuclient -batch -eval t 2>&-)" == "t" ]; then gnuclient -q "$@"; else ( xemacs "$@" &); fi } function soffice() { command soffice "$@" & } function firefox() { command firefox "$@" & } function xpdf() { command xpdf "$@" & } #------------------------------------------------------------- # File & string-related functions: #------------------------------------------------------------- # Find a file with a pattern in name: function ff() { find . -type f -iname '*'$*'*' -ls ; } # Find a file with pattern $1 in name and Execute $2 on it: function fe() { find . -type f -iname '*'${1:-}'*' -exec ${2:-file} {} \; ; } # Find a pattern in a set of files and highlight them: # (needs a recent version of egrep) function fstr() { OPTIND=1 local case="" local usage="fstr: find string in files. Usage: fstr [-i] \"pattern\" [\"filename pattern\"] " while getopts :it opt do case "$opt" in i) case="-i " ;; *) echo "$usage"; return;; esac done shift $(( $OPTIND - 1 )) if [ "$#" -lt 1 ]; then echo "$usage" return; fi find . -type f -name "${2:-*}" -print0 | \ xargs -0 egrep --color=always -sn ${case} "$1" 2>&- | more } function cuttail() # cut last n lines in file, 10 by default { nlines=${2:-10} sed -n -e :a -e "1,${nlines}!{P;N;D;};N;ba" $1 } function lowercase() # move filenames to lowercase { for file ; do filename=${file##*/} case "$filename" in */*) dirname==${file%/*} ;; *) dirname=.;; esac nf=$(echo $filename | tr A-Z a-z) newname="${dirname}/${nf}" if [ "$nf" != "$filename" ]; then mv "$file" "$newname" echo "lowercase: $file --> $newname" else echo "lowercase: $file not changed." fi done } function swap() # Swap 2 filenames around, if they exist { #(from Uzi's bashrc). local TMPFILE=tmp.$$ [ $# -ne 2 ] && echo "swap: 2 arguments needed" && return 1 [ ! -e $1 ] && echo "swap: $1 does not exist" && return 1 [ ! -e $2 ] && echo "swap: $2 does not exist" && return 1 mv "$1" $TMPFILE mv "$2" "$1" mv $TMPFILE "$2" } function extract() # Handy Extract Program. { if [ -f $1 ] ; then case $1 in *.tar.bz2) tar xvjf $1 ;; *.tar.gz) tar xvzf $1 ;; *.bz2) bunzip2 $1 ;; *.rar) unrar x $1 ;; *.gz) gunzip $1 ;; *.tar) tar xvf $1 ;; *.tbz2) tar xvjf $1 ;; *.tgz) tar xvzf $1 ;; *.zip) unzip $1 ;; *.Z) uncompress $1 ;; *.7z) 7z x $1 ;; *) echo "'$1' cannot be extracted via >extract<" ;; esac else echo "'$1' is not a valid file" fi } #------------------------------------------------------------- # Process/system related functions: #------------------------------------------------------------- function my_ps() { ps $@ -u $USER -o pid,%cpu,%mem,bsdtime,command ; } function pp() { my_ps f | awk '!/awk/ && $0~var' var=${1:-".*"} ; } function killps() # Kill by process name. { local pid pname sig="-TERM" # Default signal. if [ "$#" -lt 1 ] || [ "$#" -gt 2 ]; then echo "Usage: killps [-SIGNAL] pattern" return; fi if [ $# = 2 ]; then sig=$1 ; fi for pid in $(my_ps| awk '!/awk/ && $0~pat { print $1 }' pat=${!#} ) ; do pname=$(my_ps | awk '$1~var { print $5 }' var=$pid ) if ask "Kill process $pid <$pname> with signal $sig?" then kill $sig $pid fi done } function my_ip() # Get IP adresses. { MY_IP=$(/sbin/ifconfig ppp0 | awk '/inet/ { print $2 } ' | \ sed -e s/addr://) MY_ISP=$(/sbin/ifconfig ppp0 | awk '/P-t-P/ { print $3 } ' | \ sed -e s/P-t-P://) } function ii() # Get current host related info. { echo -e "\nYou are logged on ${RED}$HOST" echo -e "\nAdditionnal information:$NC " ; uname -a echo -e "\n${RED}Users logged on:$NC " ; w -h echo -e "\n${RED}Current date :$NC " ; date echo -e "\n${RED}Machine stats :$NC " ; uptime echo -e "\n${RED}Memory stats :$NC " ; free my_ip 2>&- ; echo -e "\n${RED}Local IP Address :$NC" ; echo ${MY_IP:-"Not connected"} echo -e "\n${RED}ISP Address :$NC" ; echo ${MY_ISP:-"Not connected"} echo -e "\n${RED}Open connections :$NC "; netstat -pan --inet; echo } #------------------------------------------------------------- # Misc utilities: #------------------------------------------------------------- function repeat() # Repeat n times command. { local i max max=$1; shift; for ((i=1; i <= max ; i++)); do # --> C-like syntax eval "$@"; done } function ask() # See 'killps' for example of use. { echo -n "$@" '[y/n] ' ; read ans case "$ans" in y*|Y*) return 0 ;; *) return 1 ;; esac } function corename() # Get name of app that created a corefile. { for file ; do echo -n $file : ; gdb --core=$file --batch | head -1 done } #========================================================================= # PROGRAMMABLE COMPLETION - ONLY SINCE BASH-2.04 # Most are taken from the bash 2.05 documentation and from Ian McDonald's # 'Bash completion' package (http://www.caliban.org/bash/#completion). # You will in fact need bash more recent than 3.0 for some features. #========================================================================= if [ "${BASH_VERSION%.*}" \< "3.0" ]; then echo "You will need to upgrade to version 3.0 \ for full programmable completion features." return fi shopt -s extglob # Necessary, #set +o nounset # otherwise some completions will fail. complete -A hostname rsh rcp telnet rlogin r ftp ping disk complete -A export printenv complete -A variable export local readonly unset complete -A enabled builtin complete -A alias alias unalias complete -A function function complete -A user su mail finger complete -A helptopic help # Currently, same as builtins. complete -A shopt shopt complete -A stopped -P '%' bg complete -A job -P '%' fg jobs disown complete -A directory mkdir rmdir complete -A directory -o default cd # Compression complete -f -o default -X '*.+(zip|ZIP)' zip complete -f -o default -X '!*.+(zip|ZIP)' unzip complete -f -o default -X '*.+(z|Z)' compress complete -f -o default -X '!*.+(z|Z)' uncompress complete -f -o default -X '*.+(gz|GZ)' gzip complete -f -o default -X '!*.+(gz|GZ)' gunzip complete -f -o default -X '*.+(bz2|BZ2)' bzip2 complete -f -o default -X '!*.+(bz2|BZ2)' bunzip2 complete -f -o default -X '!*.+(zip|ZIP|z|Z|gz|GZ|bz2|BZ2)' extract # Documents - Postscript,pdf,dvi..... complete -f -o default -X '!*.+(ps|PS)' gs ghostview ps2pdf ps2ascii complete -f -o default -X '!*.+(dvi|DVI)' dvips dvipdf xdvi dviselect dvitype complete -f -o default -X '!*.+(pdf|PDF)' acroread pdf2ps complete -f -o default -X \ '!*.@(@(?(e)ps|?(E)PS|pdf|PDF)?(.gz|.GZ|.bz2|.BZ2|.Z))' gv ggv complete -f -o default -X '!*.texi*' makeinfo texi2dvi texi2html texi2pdf complete -f -o default -X '!*.tex' tex latex slitex complete -f -o default -X '!*.lyx' lyx complete -f -o default -X '!*.+(htm*|HTM*)' lynx html2ps complete -f -o default -X \ '!*.+(doc|DOC|xls|XLS|ppt|PPT|sx?|SX?|csv|CSV|od?|OD?|ott|OTT)' soffice # Multimedia complete -f -o default -X \ '!*.+(gif|GIF|jp*g|JP*G|bmp|BMP|xpm|XPM|png|PNG)' xv gimp ee gqview complete -f -o default -X '!*.+(mp3|MP3)' mpg123 mpg321 complete -f -o default -X '!*.+(ogg|OGG)' ogg123 complete -f -o default -X \ '!*.@(mp[23]|MP[23]|ogg|OGG|wav|WAV|pls|m3u|xm|mod|s[3t]m|it|mtm|ult|flac)' xmms complete -f -o default -X \ '!*.@(mp?(e)g|MP?(E)G|wma|avi|AVI|asf|vob|VOB|bin|dat|vcd|\ ps|pes|fli|viv|rm|ram|yuv|mov|MOV|qt|QT|wmv|mp3|MP3|ogg|OGG|\ ogm|OGM|mp4|MP4|wav|WAV|asx|ASX)' xine complete -f -o default -X '!*.pl' perl perl5 # This is a 'universal' completion function - it works when commands have # a so-called 'long options' mode , ie: 'ls --all' instead of 'ls -a' # Needs the '-o' option of grep # (try the commented-out version if not available). # First, remove '=' from completion word separators # (this will allow completions like 'ls --color=auto' to work correctly). COMP_WORDBREAKS=${COMP_WORDBREAKS/=/} _get_longopts() { #$1 --help | sed -e '/--/!d' -e 's/.*--\([^[:space:].,]*\).*/--\1/'| \ #grep ^"$2" |sort -u ; $1 --help | grep -o -e "--[^[:space:].,]*" | grep -e "$2" |sort -u } _longopts() { local cur cur=${COMP_WORDS[COMP_CWORD]} case "${cur:-*}" in -*) ;; *) return ;; esac case "$1" in \~*) eval cmd="$1" ;; *) cmd="$1" ;; esac COMPREPLY=( $(_get_longopts ${1} ${cur} ) ) } complete -o default -F _longopts configure bash complete -o default -F _longopts wget id info a2ps ls recode _tar() { local cur ext regex tar untar COMPREPLY=() cur=${COMP_WORDS[COMP_CWORD]} # If we want an option, return the possible long options. case "$cur" in -*) COMPREPLY=( $(_get_longopts $1 $cur ) ); return 0;; esac if [ $COMP_CWORD -eq 1 ]; then COMPREPLY=( $( compgen -W 'c t x u r d A' -- $cur ) ) return 0 fi case "${COMP_WORDS[1]}" in ?(-)c*f) COMPREPLY=( $( compgen -f $cur ) ) return 0 ;; +([^Izjy])f) ext='tar' regex=$ext ;; *z*f) ext='tar.gz' regex='t\(ar\.\)\(gz\|Z\)' ;; *[Ijy]*f) ext='t?(ar.)bz?(2)' regex='t\(ar\.\)bz2\?' ;; *) COMPREPLY=( $( compgen -f $cur ) ) return 0 ;; esac if [[ "$COMP_LINE" == tar*.$ext' '* ]]; then # Complete on files in tar file. # # Get name of tar file from command line. tar=$( echo "$COMP_LINE" | \ sed -e 's|^.* \([^ ]*'$regex'\) .*$|\1|' ) # Devise how to untar and list it. untar=t${COMP_WORDS[1]//[^Izjyf]/} COMPREPLY=( $( compgen -W "$( echo $( tar $untar $tar \ 2>/dev/null ) )" -- "$cur" ) ) return 0 else # File completion on relevant files. COMPREPLY=( $( compgen -G $cur\*.$ext ) ) fi return 0 } complete -F _tar -o default tar _make() { local mdef makef makef_dir="." makef_inc gcmd cur prev i; COMPREPLY=(); cur=${COMP_WORDS[COMP_CWORD]}; prev=${COMP_WORDS[COMP_CWORD-1]}; case "$prev" in -*f) COMPREPLY=($(compgen -f $cur )); return 0 ;; esac; case "$cur" in -*) COMPREPLY=($(_get_longopts $1 $cur )); return 0 ;; esac; # make reads `GNUmakefile', then `makefile', then `Makefile' if [ -f ${makef_dir}/GNUmakefile ]; then makef=${makef_dir}/GNUmakefile elif [ -f ${makef_dir}/makefile ]; then makef=${makef_dir}/makefile elif [ -f ${makef_dir}/Makefile ]; then makef=${makef_dir}/Makefile else makef=${makef_dir}/*.mk # Local convention. fi # Before we scan for targets, see if a Makefile name was # specified with -f ... for (( i=0; i < ${#COMP_WORDS[@]}; i++ )); do if [[ ${COMP_WORDS[i]} == -f ]]; then # eval for tilde expansion eval makef=${COMP_WORDS[i+1]} break fi done [ ! -f $makef ] && return 0 # deal with included Makefiles makef_inc=$( grep -E '^-?include' $makef | \ sed -e "s,^.* ,"$makef_dir"/," ) for file in $makef_inc; do [ -f $file ] && makef="$makef $file" done # If we have a partial word to complete, restrict completions to # matches of that word. if [ -n "$cur" ]; then gcmd='grep "^$cur"' ; else gcmd=cat ; fi COMPREPLY=( $( awk -F':' '/^[a-zA-Z0-9][^$#\/\t=]*:([^=]|$)/ \ {split($1,A,/ /);for(i in A)print A[i]}' \ $makef 2>/dev/null | eval $gcmd )) } complete -F _make -X '+($*|*.[cho])' make gmake pmake _killall() { local cur prev COMPREPLY=() cur=${COMP_WORDS[COMP_CWORD]} # get a list of processes (the first sed evaluation # takes care of swapped out processes, the second # takes care of getting the basename of the process) COMPREPLY=( $( /usr/bin/ps -u $USER -o comm | \ sed -e '1,1d' -e 's#[]\[]##g' -e 's#^.*/##'| \ awk '{if ($0 ~ /^'$cur'/) print $0}' )) return 0 } complete -F _killall killall killps # A meta-command completion function for commands like sudo(8), which need to # first complete on a command, then complete according to that command's own # completion definition - currently not quite foolproof, # but still quite useful (By Ian McDonald, modified by me). _meta_comp() { local cur func cline cspec COMPREPLY=() cur=${COMP_WORDS[COMP_CWORD]} cmdline=${COMP_WORDS[@]} if [ $COMP_CWORD = 1 ]; then COMPREPLY=( $( compgen -c $cur ) ) else cmd=${COMP_WORDS[1]} # Find command. cspec=$( complete -p ${cmd} ) # Find spec of that command. # COMP_CWORD and COMP_WORDS() are not read-only, # so we can set them before handing off to regular # completion routine: # Get current command line minus initial command, cline="${COMP_LINE#$1 }" # split current command line tokens into array, COMP_WORDS=( $cline ) # set current token number to 1 less than now. COMP_CWORD=$(( $COMP_CWORD - 1 )) # If current arg is empty, add it to COMP_WORDS array # (otherwise that information will be lost). if [ -z $cur ]; then COMP_WORDS[COMP_CWORD]="" ; fi if [ "${cspec%%-F *}" != "${cspec}" ]; then # if -F then get function: func=${cspec#*-F } func=${func%% *} eval $func $cline # Evaluate it. else func=$( echo $cspec | sed -e 's/^complete//' -e 's/[^ ]*$//' ) COMPREPLY=( $( eval compgen $func $cur ) ) fi fi } complete -o default -F _meta_comp nohup \ eval exec trace truss strace sotruss gdb complete -o default -F _meta_comp command type which man nice time # Local Variables: # mode:shell-script # sh-shell:bash # End:

And, here is a snippet from Andrzej Szelachowski's instructive .bash_profile file.

Example L-2. .bash_profile file

# From Andrzej Szelachowski's ~/.bash_profile: # Note that a variable may require special treatment #+ if it will be exported. DARKGRAY='\e[1;30m' LIGHTRED='\e[1;31m' GREEN='\e[32m' YELLOW='\e[1;33m' LIGHTBLUE='\e[1;34m' NC='\e[m' PCT="\`if [[ \$EUID -eq 0 ]]; then T='$LIGHTRED' ; else T='$LIGHTBLUE'; fi; echo \$T \`" # For "literal" command substitution to be assigned to a variable, #+ use escapes and double quotes: #+ PCT="\` ... \`" . . . # Otherwise, the value of PCT variable is assigned only once, #+ when the variable is exported/read from .bash_profile, #+ and it will not change afterwards even if the user ID changes. PS1="\n$GREEN[\w] \n$DARKGRAY($PCT\t$DARKGRAY)-($PCT\u$DARKGRAY)-($PCT\! $DARKGRAY)$YELLOW-> $NC" # Escape a variables whose value changes: # if [[ \$EUID -eq 0 ]], # Otherwise the value of the EUID variable will be assigned only once, #+ as above. # When a variable is assigned, it should be called escaped: #+ echo \$T, # Otherwise the value of the T variable is taken from the moment the PCT #+ variable is exported/read from .bash_profile. # So, in this example it would be null. # When a variable's value contains a semicolon it should be strong quoted: # T='$LIGHTRED', # Otherwise, the semicolon will be interpreted as a command separator. # Variables PCT and PS1 can be merged into a new PS1 variable: PS1="\`if [[ \$EUID -eq 0 ]]; then PCT='$LIGHTRED'; else PCT='$LIGHTBLUE'; fi; echo '\n$GREEN[\w] \n$DARKGRAY('\$PCT'\t$DARKGRAY)-\ ('\$PCT'\u$DARKGRAY)-('\$PCT'\!$DARKGRAY)$YELLOW-> $NC'\`" # The trick is to use strong quoting for parts of old PS1 variable.