PS1 variable in single and double quotes - bashrc

Question

I've set my bashrc file as follows (for Git Bash)

source ~/git-prompt.sh
source ~/git-completion.bash
export GIT_PS1_SHOWDIRTYSTATE=true
PS1='\[\e[0;37m\]\342\224\214\342\224\200[\[\e[0m\]\[\e[1;32m\]\u\[\e[0;37m\]:\[\e[1;34m\]\h\[\e[0;37m\]]\342\224\200[\[\e[33m\]\W\[\e[0;37m\]]\342\224\200[\[\e[1;33m\]\@\[\e[0m\]]$(__git_ps1)\n\[\e[0;37m\]\342\224\224\342\224\200\342\224\200\[\e[1;36m\]\$\[\e[0m\] '

ignoring the octal characters, it shortens down to:

PS1='\[\e[0;37m\]-[\[\e[0m\]\[\e[1;32m\]\u\[\e[0;37m\]:\[\e[1;34m\]\h\[\e[0;37m\]]-[\[\e[33m\]\W\[\e[0;37m\]]-[\[\e[1;33m\]\@\[\e[0m\]]$(__git_ps1)\n\[\e[0;37m\]-\[\e[1;36m\]\$\[\e[0m\] '

This works just fine, except for when I try to get the command status symbols by using the following segment (as seen on ArchWiki):

\$([[ \$? != 0 ]] && echo \"[\[\e[1;31m\]X\[\e[0;37m\]]-\") # again, shortened the octal codes for readability

The only different I noticed was the usage of double quotes on ArchWiki and single quotes in my case. So, I used double-quotes in my file as well:

PS1="\[\e[0;37m\]\$([[ \$? != 0 ]] && echo \"[\[\e[1;31m\]X\[\e[0;37m\]]-\")-[\[\e[0m\]\[\e[1;32m\]\u\[\e[0;37m\]:\[\e[1;34m\]\h\[\e[0;37m\]]-[\[\e[33m\]\W\[\e[0;37m\]]-[\[\e[1;33m\]\@\[\e[0m\]]$(__git_ps1)\n\[\e[0;37m\]-\[\e[1;36m\]\$\[\e[0m\] "

and then include the aforementioned segment of code:

PS1="\[\e[0;37m\]-[\[\e[0m\]\[\e[1;32m\]\u\[\e[0;37m\]:\[\e[1;34m\]\h\[\e[0;37m\]]-[\[\e[33m\]\W\[\e[0;37m\]]-[\[\e[1;33m\]\@\[\e[0m\]]$(__git_ps1)\n\[\e[0;37m\]-\[\e[1;36m\]\$\[\e[0m\] "

This works fine, except that my git-auto-completion no longer functions. If I move into a git repository, the $(__git_ps1) returns nothing. If I restart bash from inside a git repo, it displays the current branch but again fails to execute when I leave the directory or switch branch.

Is there a difference in the following statements:

x="yzx"
x='yzx'

PS

The environment in Windows 7, in case someone wonders.

Answer 1

In your case, you have a number of escape characters using \. The difference between "..." and '...' is that the shell peeks inside the double quotes to interpret escape sequences whereas in the case of single quotes, it takes the backslash literally. Try the following:

echo '\$foo'
echo "\$foo"

and you will see the difference.