I am a newbie and I want to use linux bashrc

Question

So I am a newbie in using Linux and I am following courses and blog posts related to linux to learn more and more about it. As I was searching about Linux Bashrc, what it is and how to use it, I came across a piece of code to change the color of the shell when a command fails to work properly. I read about the linux bashrc in the linked article, but my problem is the following lines.

This prompt changes the color if your last command failed to run successfully, but it also shortens long paths and contains the bash history number of each command for easy retrieval. This can be very helpful and efficient.

PROMPT_COMMAND='PS1="\[\033[0;33m\][\!]\'if [[ \$? = "0" ]];
then echo "\\[\\033[32m\\]"; else echo "\\[\\033[31m\\]";

fi\'[\u.\h: \'if [[ \pwd|WC -c|tr -d " "' > 18 ]]; then echo

"\\W"; else echo "\\w"; fi\']\$\[\033[0m\] "; echo -ne

"\033]0; hostname -s':'pwed'\007"'

I write exactly as this code says but still I get nothing, what could be the problem? I'd appreciate it if anyone could help me.

Answer 1

what could be the problem?

It seems the code started as an unsophisticated cumbersome one-liner which actually worked. Then it was badly crippled by humans (someone wrote it down and somebody else retyped?) and(?) machines (some characters were translated?); not necessarily in this order.

Now it's garbage. Even in its original (supposedly working) form it was a frenzy of quoting and escaping. Probably this:

PROMPT_COMMAND='PS1="\[\033[0;33m\][\!]`if [[ \$? = "0" ]]; then echo "\\[\\033[32m\\]"; else echo "\\[\\033[31m\\]"; fi`[\u.\h: `if [[ \`pwd|wc -c|tr -d " "\` > 18 ]]; then echo "\\W"; else echo "\\w"; fi`]\$\[\033[0m\] "; echo -ne "\033]0;`hostname -s`:`pwd`\007"'

Converted to a less cumbersome piece of code:

_prompt_f() {

if [[ $? = "0" ]]; then
   PS1='\[\033[32m\]'
else
   PS1='\[\033[31m\]'
fi

PS1='\[\033[0;33m\][\!]'"$PS1"'[\u.\h: '

if [[ "$(pwd | wc -c)" > 18 ]]; then
   PS1="$PS1\W"
else
   PS1="$PS1\w"
fi

PS1="$PS1]\$\[\033[0m\] "

printf '\033]0;%s:%s\007' "$(hostname -s)" "$(pwd)"
}

PROMPT_COMMAND=_prompt_f