Bash prompt not recognizing Unicode escapes

bashpromptquoting

I'm trying to customize my Bash prompt with Unicode characters and I'm having a bit of trouble. If I try to include a Unicode character like this:

$ echo ☢ | hexdump -C
00000000  e2 98 a2 0a                                       |....|
00000004

$ PS1="\xe2\x98\xa2\x0a"

I see my prompt appears like this:

\xe2\x98\xa2\x0a

…rather than showing the ☢ character. What am I doing wrong?

Best Answer

That's not valid bash escape syntax for simple double quotes. Try instead

PS1=$'\xe2\x98\xa2 '

This uses the special $'...' quoting that bash has and which does support ANSI C escapes. Note that the 0a is just linefeed (newline character) and I doubt you want that, so I took the liberty of replacing it with a space above.

Of course, instead of going through the entire rigamarole of finding the UTF-8 encoding, and then typing out the escapes, you could just use the raw character itself (PS1='☢ ') and it would still work.

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PROMPT_COMMAND='echo -en "\033[38;5;2m"; history 1; echo -en "\033[0m\n"'

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If you need to integrate that in a complex prompt set via PROMPT_COMMAND (which is a bash setting, by the way, so shouldn't be exported):

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By the way, this should all go into ~/.bashrc, not ~/.bash_profile (see Difference between .bashrc and .bash_profile). ~/.bashrc is run in every bash instance and contains shell customizations such as prompts and aliases. ~/.bash_profile is run when you log in (if your login shell is bash). Oddly, bash doesn't read ~/.bashrc in login shells, so your ~/.bash_profile should contain

case $- in *i*) . ~/.bashrc;; esac

Best Answer

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