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bash - BASH 提示符中的正确返回值

问题描述

这是.bashrc在 Ubuntu 19.10 机器上设置提示的文件的一部分：

# Terminal tab name in gnome-terminal or Guake
PROMPT_COMMAND='echo -ne "\033]0;$(basename ${PWD})\007"'

GIT_PS1_SHOWCOLORHINTS=yes
RET=\$?
source /usr/lib/git-core/git-sh-prompt

if [ "$color_prompt" = yes ]; then
    color_reset=$(tput sgr0)
    color_bold=$(tput bold)
    color_white=$(tput setaf 7)
    color_jobs=$(tput setaf 7)
    color_user=$(tput setaf 3)
    color_dir=$(tput setaf 4)
    color_load=$(tput setaf 5)
    color_succeed=$(tput setaf 2)
    color_fail=$(tput setaf 1)
    sep=$(tput setaf 7)\)
    PS1="${color_user}\u${sep}\[\D{%T}\]${sep}${color_reset}\$(__git_ps1)${color_dir}\W${color_reset}${sep}\`if [[ ${RET} == 0 ]]; then echo \"${color_succeed}0\"; else echo \"${color_fail}${RET}\"; fi\`${color_white}${sep}${color_reset}\$ "
else
    PS1="\u${sep}\[\D{%T}\]${sep}\$(__git_ps1)\W${sep}\`if [[ ${RET} == 0 ]]; then echo \"0\"; else echo \"${RET}\"; fi\`${sep}\$ "
fi

这是正在使用的命令行示例：

snim2)10:39:53)dirname)0)$ cd scratch
snim2)10:39:54)scratch)0)$ git init
Initialised empty Git repository in .../scratch/.git/
snim2)10:39:56) (master)scratch)0)$ asdasda
asdasda: command not found
snim2)10:40:05) (master)scratch)1)$ $?
127: command not found
snim2)10:40:10) (master)scratch)1)$

如您所见，当命令的返回码不为零时，它会显示1)在提示符中，而不是显示正确的返回码——在这种情况下127)。如何解决这个问题？

标签： bashpromptps1

解决方案

你做：

..$(__git_ps1)...\`if [[ $? == 0 ]];

这$?将是__git_ps1不是命令行上最后执行的命令的返回状态。

尝试立即将退出返回值保存在第一个命令替换块中：

if [ "$color_prompt" = yes ]; then
    color_reset=$(tput sgr0)
    color_bold=$(tput bold)
    color_white=$(tput setaf 7)
    color_jobs=$(tput setaf 7)
    color_user=$(tput setaf 3)
    color_dir=$(tput setaf 4)
    color_load=$(tput setaf 5)
    color_succeed=$(tput setaf 2)
    color_fail=$(tput setaf 1)
    sep=$(tput setaf 7)\)
else
    color_reset=
    color_bold=
    color_white=
    color_jobs=
    color_user=
    color_dir=
    color_load=
    color_succeed=
    color_fail=
    sep=\)  # remove the braces...
fi

# note the quotes - "" expand at setting time, '' expand at runtime
PS1=
PS1+="${color_user}\u${sep}\[\D{%T}\]${sep}${color_reset}"
PS1+='$('
   PS1+='ret=$?; '  # first thing we do - save the exit return value
   PS1+='__git_ps1; '
   PS1+='printf "%s" "'
      PS1+="${color_dir}\W${color_reset}${sep}"
      PS1+='"; '
   PS1+='if ((ret == 0)); then '
       PS1+='printf "%s" "'
          PS1+="${color_succeed}"  # expand variable on assignment side
          PS1+='0"; '  # this looks strange. Just print first the color, then $ret...
   PS1+='else '
      PS1+='printf "%s" "'
           PS1+="$color_fail"
           PS1+='$ret"; '
   PS1+='fi '
PS1+=')'
PS1+="${color_white}${sep}${color_reset}"
PS1+='\$ '  # note - this is *not* "\$ "

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