Ubuntu每次打开终端出现错误提示的解决方法

每次打开终端会出现问题，那就说明bashrc文件出现问题，

第一步，排除法，确定是哪个用户的哪个bashrc文件出现问题

切换到root用户登陆，打开终端，结果没有出现问题，说明问题出现在jeremy用户上
切回jeremy用户，寻找是哪个bashrc文件，将/home/jeremy/.bashrc的bashrc文件移动到其他文件夹，结果打开后，错误消失，说明，问题出现在这个文件。

第二步，研究这个文件哪里调用了ovs-vsctl命令
.bashrc文件的内容如下

# ~/.bashrc: executed by bash(1) for non-login shells.
# see /usr/share/doc/bash/examples/startup-files (in the package bash-doc)
# for examples

# If not running interactively, don't do anything
case $- in
    *i*) ;;
      *) return;;
esac

# don't put duplicate lines or lines starting with space in the history.
# See bash(1) for more options
HISTCONTROL=ignoreboth

# append to the history file, don't overwrite it
shopt -s histappend

# for setting history length see HISTSIZE and HISTFILESIZE in bash(1)
HISTSIZE=1000
HISTFILESIZE=2000

# check the window size after each command and, if necessary,
# update the values of LINES and COLUMNS.
shopt -s checkwinsize

# If set, the pattern "**" used in a pathname expansion context will
# match all files and zero or more directories and subdirectories.
#shopt -s globstar

# make less more friendly for non-text input files, see lesspipe(1)
[ -x /usr/bin/lesspipe ] && eval "$(SHELL=/bin/sh lesspipe)"

# set variable identifying the chroot you work in (used in the prompt below)
if [ -z "${debian_chroot:-}" ] && [ -r /etc/debian_chroot ]; then
    debian_chroot=$(cat /etc/debian_chroot)
fi

# set a fancy prompt (non-color, unless we know we "want" color)
case "$TERM" in
    xterm-color) color_prompt=yes;;
esac

# uncomment for a colored prompt, if the terminal has the capability; turned
# off by default to not distract the user: the focus in a terminal window
# should be on the output of commands, not on the prompt
#force_color_prompt=yes

if [ -n "$force_color_prompt" ]; then
    if [ -x /usr/bin/tput ] && tput setaf 1 >&/dev/null; then
    # We have color support; assume it's compliant with Ecma-48
    # (ISO/IEC-6429). (Lack of such support is extremely rare, and such
    # a case would tend to support setf rather than setaf.)
    color_prompt=yes
    else
    color_prompt=
    fi
fi

if [ "$color_prompt" = yes ]; then
    PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
else
    PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '
fi
unset color_prompt force_color_prompt

# If this is an xterm set the title to user@host:dir
case "$TERM" in
xterm*|rxvt*)
    PS1="\[\e]0;${debian_chroot:+($debian_chroot)}\u@\h: \w\a\]$PS1"
    ;;
*)
    ;;
esac

# enable color support of ls and also add handy aliases
if [ -x /usr/bin/dircolors ]; then
    test -r ~/.dircolors && eval "$(dircolors -b ~/.dircolors)" || eval "$(dircolors -b)"
    alias ls='ls --color=auto'
    #alias dir='dir --color=auto'
    #alias vdir='vdir --color=auto'

    alias grep='grep --color=auto'
    alias fgrep='fgrep --color=auto'
    alias egrep='egrep --color=auto'
fi

# some more ls aliases
alias ll='ls -alF'
alias la='ls -A'
alias l='ls -CF'

# Add an "alert" alias for long running commands.  Use like so:
#   sleep 10; alert
alias alert='notify-send --urgency=low -i "$([ $? = 0 ] && echo terminal || echo error)" "$(history|tail -n1|sed -e '\''s/^\s*[0-9]\+\s*//;s/[;&|]\s*alert$//'\'')"'

# Alias definitions.
# You may want to put all your additions into a separate file like
# ~/.bash_aliases, instead of adding them here directly.
# See /usr/share/doc/bash-doc/examples in the bash-doc package.

if [ -f ~/.bash_aliases ]; then
    . ~/.bash_aliases
fi

# enable programmable completion features (you don't need to enable
# this, if it's already enabled in /etc/bash.bashrc and /etc/profile
# sources /etc/bash.bashrc).
if ! shopt -oq posix; then
  if [ -f /usr/share/bash-completion/bash_completion ]; then
   . /usr/share/bash-completion/bash_completion
  elif [ -f /etc/bash_completion ]; then
   . /etc/bash_completion
  fi
fi

先搜索ovs系列的语句，结果在这个文件里面没找到，说明这个文件调用了其他文件的ovs命令，接下来只需查找调用其他文件的执行命令，这里不需要一步一步的看，我的方法是，注释一段语句，再打开终端，如果问题没有出现了，就说明问题就出现在这段语句中。经过直觉的判断，我直接注释了最后一段if语句
if ! shopt -oq posix; then
  if [ -f /usr/share/bash-completion/bash_completion ]; then
   . /usr/share/bash-completion/bash_completion
  elif [ -f /etc/bash_completion ]; then
   . /etc/bash_completion
  fi
fi
结果问题没有了，仔细看这段if语句，它的大意是如果/usr/share/bash-completion/bash_completion这个文件存在，就执行这个文件，这就说明问题出现在bash_completion这个文件里面。

第三步，继续查找/usr/share/bash-completion/bash_completion出现的问题

这个sh文件有1000多行，刚开始被吓到，但还是有套路的，先搜索ovs，结果没找到，说明还是继续调用的其他ovs文件。仔细扫了一遍之后，发现里面大部分是函数，所以函数部分不用看，直接从执行部分看起，还是按照第二步来，查看调用其他sh文件的语句，结果找到这段if语句
if [[ -d $BASH_COMPLETION_COMPAT_DIR && -r $BASH_COMPLETION_COMPAT_DIR && \
    -x $BASH_COMPLETION_COMPAT_DIR ]]; then
    for i in $(LC_ALL=C command ls "$BASH_COMPLETION_COMPAT_DIR"); do
        i=$BASH_COMPLETION_COMPAT_DIR/$i
        [[ ${i##*/} != @($_backup_glob|Makefile*|$_blacklist_glob) \
            && -f $i && -r $i ]] && . "$i"
    done
fi
而BASH_COMPLETION_COMPAT_DIR=/etc/bash_completion.d
所以直接进入/etc/bash_completion.d查找文件，结果找到

发现ovs*文件，问题就出现在这里，把关于ovs*的文件移出到其他文件后，打开终端就没有问题了
问题就到这里解决。

第四步：总结
如果每次打开终端，都会出现问题，就可以判断出问题出现在～/.bashrc文件，然后再一一筛除。