一些变量未显示在提示中Bash

如何解决一些变量未显示在提示中Bash

有些变量没有显示，在这种情况下，这个 PS_GIT 变量

#!/usr/bin/bash

# Other codes
# ...

export USER=""
export HOSTNAME=""

RESET="\[\033[0m\]"
RED="\[\033[0;31m\]"
GREEN="\[\033[01;32m\]"
BLUE="\[\033[01;34m\]"
YELLOW="\[\033[0;33m\]"

function parse_git_branch {
    PS_BRANCH=""

    if [ -d .svn ] ; then
        PS_BRANCH="(svn r$(svn info|awk '/Revision/{print $2}'))"
        return
    elif [ -f _FOSSIL_ -o -f .fslckout ]; then
        PS_BRANCH="(fossil $(fossil status|awk '/tags/{print $2}')) "
        return
    fi

    ref=$(git symbolic-ref HEAD 2> /dev/null) || return
    PS_BRANCH="(git ${ref#refs/heads/}) "
}

PROMPT_COMMAND=parse_git_branch

PS_INFO="${GREEN}${USER}${RESET}@${GREEN}${HOSTNAME}${RESET}:${BLUE}\w"
PS_GIT="${YELLOW}${PS_BRANCH}"
PS_TIME=" ${RED}[\t]${RESET}"

export PS1="\[\033[0G\]${PS_INFO} ${PS_GIT}${PS_TIME}\n${RESET}\$ "

在目录中时，我运行 echo $PS_BRANCH 并显示 (git main)，因此我知道该变量有效。但是，它没有在提示处显示

Screenshot example