Bash 使用指南

本文收集了主流 Linux 发行版的默认 Bash 配置和实用代码片段，帮助您更好地配置和使用 Bash Shell。

Bash 简介

Bash（Bourne Again SHell）是 Linux 和 macOS 系统中最常用的 Shell 之一，具有以下特点：

• 命令行解释器
• 脚本编程语言
• 任务自动化
• 命令历史记录

Manjaro 默认配置

System-wide Config (/etc/bash.bashrc)

This file contains system-wide settings for interactive shells.

/etc/bash.bashrc

#
#

# If not running interactively, don't do anything
[[ $- != *i* ]] && return

[[ $DISPLAY ]] && shopt -s checkwinsize

PS1='[\u@\h \W]\$ '

case ${TERM} in
  xterm*|rxvt*|Eterm|aterm|kterm|gnome*)
    PROMPT_COMMAND=${PROMPT_COMMAND:+$PROMPT_COMMAND; }'printf "\033]0;%s@%s:%s\007" "${USER}" "${HOSTNAME%%.*}" "${PWD/#$HOME/\~}"'

    ;;
  screen*)
    PROMPT_COMMAND=${PROMPT_COMMAND:+$PROMPT_COMMAND; }'printf "\033_%s@%s:%s\033\\" "${USER}" "${HOSTNAME%%.*}" "${PWD/#$HOME/\~}"'
    ;;
esac

[ -r /usr/share/bash-completion/bash_completion   ] && . /usr/share/bash-completion/bash_completion

用户配置文件 (~/.bashrc)

用户配置文件包含个人特定的设置、别名和函数。

~/.bashrc

#
#

# 如果不是交互式 Shell，不执行任何操作
[[ $- != *i* ]] && return

# 颜色配置函数
colors() {
        local fgc bgc vals seq0

        printf "Color escapes are %s\n" '\e[${value};...;${value}m'
        printf "Values 30..37 are \e[33mforeground colors\e[m\n"
        printf "Values 40..47 are \e[43mbackground colors\e[m\n"
        printf "Value  1 gives a  \e[1mbold-faced look\e[m\n\n"

        # 前景颜色
        for fgc in {30..37}; do
                # 背景颜色
                for bgc in {40..47}; do
                        fgc=${fgc#37} # white
                        bgc=${bgc#40} # black

                        vals="${fgc:+$fgc;}${bgc}"
                        vals=${vals%%;}

                        seq0="${vals:+\e[${vals}m}"
                        printf "  %-9s" "${seq0:-(default)}"
                        printf " ${seq0}TEXT\e[m"
                        printf " \e[${vals:+${vals+$vals;}}1mBOLD\e[m"
                done
                echo; echo
        done
}

# 加载 Bash 自动补全
[ -r /usr/share/bash-completion/bash_completion ] && . /usr/share/bash-completion/bash_completion

# 更改 X 终端的窗口标题
case ${TERM} in
        xterm*|rxvt*|Eterm*|aterm|kterm|gnome*|interix|konsole*)
                PROMPT_COMMAND='echo -ne "\033]0;${USER}@${HOSTNAME%%.*}:${PWD/#$HOME/\~}\007"'
                ;;
        screen*)
                PROMPT_COMMAND='echo -ne "\033_${USER}@${HOSTNAME%%.*}:${PWD/#$HOME/\~}\033\\"'
                ;;
esac

use_color=true

# 设置彩色 PS1（仅在彩色终端上）
safe_term=${TERM//[^[:alnum:]]/?}   # 清理 TERM
match_lhs=""
[[ -f ~/.dir_colors   ]] && match_lhs="${match_lhs}$(<~/.dir_colors)"
[[ -f /etc/DIR_COLORS ]] && match_lhs="${match_lhs}$(</etc/DIR_COLORS)"
[[ -z ${match_lhs}    ]] \
        && type -P dircolors >/dev/null \
        && match_lhs=$(dircolors --print-database)
[[ $'\n'${match_lhs} == *$'\n'"TERM "${safe_term}* ]] && use_color=true

if ${use_color} ; then
        # 启用 ls 等命令的颜色
        if type -P dircolors >/dev/null ; then
                if [[ -f ~/.dir_colors ]] ; then
                        eval $(dircolors -b ~/.dir_colors)
                elif [[ -f /etc/DIR_COLORS ]] ; then
                        eval $(dircolors -b /etc/DIR_COLORS)
                fi
        fi

        if [[ ${EUID} == 0 ]] ; then
                PS1='\[\033[01;31m\][\h\[\033[01;36m\] \W\[\033[01;31m\]]\$\[\033[00m\] '
        else
                PS1='\[\033[01;32m\][\u@\h\[\033[01;37m\] \W\[\033[01;32m\]]\$\[\033[00m\] '
        fi

        alias ls='ls --color=auto'
        alias grep='grep --colour=auto'
        alias egrep='egrep --colour=auto'
        alias fgrep='fgrep --colour=auto'
else
        if [[ ${EUID} == 0 ]] ; then
                # 没有颜色时显示 root@
                PS1='\u@\h \W \$ '
        else
                PS1='\u@\h \w \$ '
        fi
fi

unset use_color safe_term match_lhs sh

# 常用别名
alias cp="cp -i"                          # 覆盖前确认
alias df='df -h'                          # 人类可读的大小
alias free='free -m'                      # 以 MB 显示大小
alias np='nano -w PKGBUILD'
alias more=less

xhost +local:root > /dev/null 2>&1

complete -cf sudo

# Bash won't get SIGWINCH if another process is in the foreground.
# Enable checkwinsize so that bash will check the terminal size when
# it regains control.  #65623
# http://cnswww.cns.cwru.edu/~chet/bash/FAQ (E11)
shopt -s checkwinsize

shopt -s expand_aliases

# export QT_SELECT=4

# Enable history appending instead of overwriting.  #139609
shopt -s histappend

实用代码片段

解压工具函数 (ex)

一个方便的函数，用于使用单个命令解压各种格式的归档文件。

#
# # ex - 归档解压工具
# # 用法: ex <文件>
ex ()
{
  if [ -f $1 ] ; then
    case $1 in
      *.tar.bz2)   tar xjf $1   ;;
      *.tar.gz)    tar xzf $1   ;;
      *.bz2)       bunzip2 $1   ;;
      *.rar)       unrar x $1     ;;
      *.gz)        gunzip $1    ;;
      *.tar)       tar xf $1    ;;
      *.tbz2)      tar xjf $1   ;;
      *.tgz)       tar xzf $1   ;;
      *.zip)       unzip $1     ;;
      *.Z)         uncompress $1;;
      *.7z)        7z x $1      ;;
      *)           echo "'$1' cannot be extracted via ex()" ;;
    esac
  else
    echo "'$1' is not a valid file"
  fi
}