编辑~/.ps1，代码如下：

#!/bin/bash
# bash PS1 setter
# install: echo '. ./ps1bash' >> ~/.bashrc
# uninstall: unset PROMPT_COMMAND;PS1='[\u@\h \W]\$ '
# https://wiki.archlinux.org/index.php/Color_Bash_Prompt

txtblk='\e[0;30m' # Black - Regular
txtred='\e[0;31m' # Red
txtgrn='\e[0;32m' # Green
txtylw='\e[0;33m' # Yellow
txtblu='\e[0;34m' # Blue
txtpur='\e[0;35m' # Purple
txtcyn='\e[0;36m' # Cyan
txtwht='\e[0;37m' # White
bldblk='\e[1;30m' # Black - Bold
bldred='\e[1;31m' # Red
bldgrn='\e[1;32m' # Green
bldylw='\e[1;33m' # Yellow
bldblu='\e[1;34m' # Blue
bldpur='\e[1;35m' # Purple
bldcyn='\e[1;36m' # Cyan
bldwht='\e[1;37m' # White
unkblk='\e[4;30m' # Black - Underline
undred='\e[4;31m' # Red
undgrn='\e[4;32m' # Green
undylw='\e[4;33m' # Yellow
undblu='\e[4;34m' # Blue
undpur='\e[4;35m' # Purple
undcyn='\e[4;36m' # Cyan
undwht='\e[4;37m' # White
bakblk='\e[40m'   # Black - Background
bakred='\e[41m'   # Red
bakgrn='\e[42m'   # Green
bakylw='\e[43m'   # Yellow
bakblu='\e[44m'   # Blue
bakpur='\e[45m'   # Purple
bakcyn='\e[46m'   # Cyan
bakwht='\e[47m'   # White
txtrst='\e[0m'    # Text Reset

#\342\224\214
#[liao@tp bin]$ echo -e "\0342\0224\0214"
#┌
r='\342\224\214'

#\342\224\200
#[liao@tp bin]$ echo -e "\0342\0224\0200"
#─
hyphen='\342\224\200'

#\342\224\224
#[liao@tp bin]$ echo -e "\0342\0224\0224"
#└
l='\342\224\224'

#\342\234\227
#[liao@tp bin]$ echo -e "\0342\0234\0227"
#✗
x='\342\234\227'

get_ps1()
{
[ $? != 0 ] && lc_rslt=[${txtred}${x}${txtrst}]${hyphen} || unset lc_rslt
[ ${EUID} == 0 ] && uc=${txtred} || uc=${txtylw}
dn=$(ls -l | grep ^d | wc -l);fn=$(expr $(ls | wc -l) - ${dn})
PS1="${r}${hyphen}${lc_rslt}[${uc}\u${txtrst}@${txtcyn}\h${txtrst}]${hyphen}[${txtpur}\w${txtrst}]${hyphen}[${txtgrn}${fn}+${dn}${txtrst}]${txtrst}\n${l}\\$ "
}

PROMPT_COMMAND=get_ps1

然后加到~/.bashrc中

...
source ~/.ps1

搞定啦！