CODEWITHSUNDEEP
bash
Bruce Johnson
Bruce Johnson

Reputation: 49

Bash prompt multiple command substitution

I am setting up my bash prompt in .bashrc using the following (simplified) function:

set_prompts() {

    PS1="\u@\h in \w "
    PS1+="\$(get_git_repo_details)"
    PS1+="\n"
    PS1+="\$(exit_status_prompt)"
}

Now the exit_status_prompt prints a different coloured prompt character, depending on whether the value of $? is 0 or not.

What I noticed though, is that with the code as above, the colour of the prompt character never updates. However, if I append the output of exit_status_prompt to $PS1 before I append the output of get_git_repo_details, or don't append the output of get_git_repo_details at all, then it does update.

Does anyone know what is causing this? Thanks.

Edit:

exit_status_prompt()
{
    if [ $? -ne 0 ]
    then
        highlight 1 "❯ "
    else
        highlight 2 "❯ "
    fi
}

The highlight function then just uses tput to prepend the string in the second parameter with the colour specified in the first parameter.

Upvotes: 3

Views: 371

Answers (1)

chepner
chepner

Reputation: 531918

You need to call exit_status_prompt before doing anything else in set_prompts, or $? is going to be reset. Presumably, exit_status_prompt uses the exit status of the most recently executed command or assignment.

set_prompts() {
    esp=$(exit_status_prompt)
    PS1="\u@\h in \w "
    PS1+="$(get_git_repo_details)"
    PS1+="\n"
    PS1+="$esp"
}

I've unescaped the command substitutions, because I assume that you are (and should be) running set_prompts as the first command in PROMPT_COMMAND.

Upvotes: 2

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