linux-alias的使用（定义自己习惯的命令）

在使用Ubuntu的过程中，有些命令在输入中十分的不顺手，部分是不熟练的原因，也有有一部分是习惯的原因，利用用惯了Windows下的shell或powershell，在清屏的时候习惯的使用cls，而在Linux下为clear，十分的不习惯，在Linux下有可以使用alias进行自定义，定义出自己的习惯的命令。

语法：alias [别名]=[指令名称]

alias cls='clear'

在Terminal下，输入上面的代码就可以将cls和clear有同样的功能，不过在开关机之后这样的命令的就失效了，只能暂时的使用。

如果想在每次打开Terminal，使用清屏的时候都是cls替代clear,可以在.bashrc下进行修改

打开.bashrc文件可以看到下面的内容（在下面的文件已经对cls替代clear进行了修改98行），使用vim或其他的编译器对.bashrc进行修改，并保存，重新打开Terminal，就可以使用cls命令了。

     1  # ~/.bashrc: executed by bash(2) for non-login shells.     2  # see /usr/share/doc/bash/examples/startup-files (in the package bash-doc)     3  # for examples     4       5  # If not running interactively, don't do anything     6  case $- in     7      *i*) ;;     8        *) return;;     9  esac    10      11  # don't put duplicate lines or lines starting with space in the history.    12  # See bash(1) for more options    13  HISTCONTROL=ignoreboth    14      15  # append to the history file, don't overwrite it    16  shopt -s histappend    17      18  # for setting history length see HISTSIZE and HISTFILESIZE in bash(1)    19  HISTSIZE=1000    20  HISTFILESIZE=2000    21      22  # check the window size after each command and, if necessary,    23  # update the values of LINES and COLUMNS.    24  shopt -s checkwinsize    25      26  # If set, the pattern "**" used in a pathname expansion context will    27  # match all files and zero or more directories and subdirectories.    28  #shopt -s globstar    29      30  # make less more friendly for non-text input files, see lesspipe(1)    31  [ -x /usr/bin/lesspipe ] && eval "$(SHELL=/bin/sh lesspipe)"    32      33  # set variable identifying the chroot you work in (used in the prompt below)    34  if [ -z "${debian_chroot:-}" ] && [ -r /etc/debian_chroot ]; then    35      debian_chroot=$(cat /etc/debian_chroot)    36  fi    37      38  # set a fancy prompt (non-color, unless we know we "want" color)    39  case "$TERM" in    40      xterm-color|*-256color) color_prompt=yes;;    41  esac    42      43  # uncomment for a colored prompt, if the terminal has the capability; turned    44  # off by default to not distract the user: the focus in a terminal window    45  # should be on the output of commands, not on the prompt    46  #force_color_prompt=yes    47      48  if [ -n "$force_color_prompt" ]; then    49      if [ -x /usr/bin/tput ] && tput setaf 1 >&/dev/null; then    50      # We have color support; assume it's compliant with Ecma-48    51      # (ISO/IEC-6429). (Lack of such support is extremely rare, and such    52      # a case would tend to support setf rather than setaf.)    53      color_prompt=yes    54      else    55      color_prompt=    56      fi    57  fi    58      59  if [ "$color_prompt" = yes ]; then    60      PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '    61  else    62      PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '    63  fi    64  unset color_prompt force_color_prompt    65      66  # If this is an xterm set the title to user@host:dir    67  case "$TERM" in    68  xterm*|rxvt*)    69      PS1="\[\e]0;${debian_chroot:+($debian_chroot)}\u@\h: \w\a\]$PS1"    70      ;;    71  *)    72      ;;    73  esac    74      75  # enable color support of ls and also add handy aliases    76  if [ -x /usr/bin/dircolors ]; then    77      test -r ~/.dircolors && eval "$(dircolors -b ~/.dircolors)" || eval "$(dircolors -b)"    78      alias ls='ls --color=auto'    79      #alias dir='dir --color=auto'    80      #alias vdir='vdir --color=auto'    81      82      alias grep='grep --color=auto'    83      alias fgrep='fgrep --color=auto'    84      alias egrep='egrep --color=auto'    85  fi    86      87  # colored GCC warnings and errors    88  #export GCC_COLORS='error=01;31:warning=01;35:note=01;36:caret=01;32:locus=01:quote=01'    89      90  # some more ls aliases    91  alias ll='ls -alF'    92  alias la='ls -A'    93  alias l='ls -CF'    94  alias cls='cls'    95      96  # ------begin----------    97  # person aliases    98  alias cls='clear'    99     100     101  # ------end----------   102     103  # Add an "alert" alias for long running commands.  Use like so:   104  #   sleep 10; alert   105  alias alert='notify-send --urgency=low -i "$([ $? = 0 ] && echo terminal || echo error)" "$(history|tail -n1|sed -e '\''s/^\s*[0-9]\+\s*//;s/[;&|]\s*alert$//'\'')"'   106     107  # Alias definitions.   108  # You may want to put all your additions into a separate file like   109  # ~/.bash_aliases, instead of adding them here directly.   110  # See /usr/share/doc/bash-doc/examples in the bash-doc package.   111     112  if [ -f ~/.bash_aliases ]; then   113      . ~/.bash_aliases   114  fi   115     116  # enable programmable completion features (you don't need to enable   117  # this, if it's already enabled in /etc/bash.bashrc and /etc/profile   118  # sources /etc/bash.bashrc).   119  if ! shopt -oq posix; then   120     121    if [ -f /usr/share/bash-completion/bash_completion ]; then   122      . /usr/share/bash-completion/bash_completion   123    elif [ -f /etc/bash_completion ]; then   124      . /etc/bash_completion   125    fi   126  fi