Bash提示多命令替换 [英] Bash prompt multiple command substitution

问题描述

我正在使用以下(简化的)函数在.bashrc中设置我的bash提示符:

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)"
}

现在，根据 $?的值是否为0， exit_status_prompt 将打印不同的彩色提示字符.

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

我注意到的是，使用上面的代码，提示字符的颜色从不更新.但是，如果在将 get_git_repo_details 的输出附加到 $ PS1 之前，将 exit_status_prompt 的输出附加到 $ PS1 ，或者不附加 get_git_repo_details ，然后会更新.

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.

有人知道是什么原因造成的吗?谢谢.

Does anyone know what is causing this? Thanks.

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

然后， highlight 函数仅使用 tput 在第二个参数中的字符串前加上第一个参数中指定的颜色.

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

推荐答案

您需要先调用 exit_status_prompt ，然后再执行 set_prompts 或 $?将被重置.大概， exit_status_prompt 使用最近执行的命令或赋值的退出状态.

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"
}

我已经取消了命令替换，因为我假设您正在(并且应该)运行 set_prompts 作为 PROMPT_COMMAND 中的第一条命令.

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.

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