Bash下實現自定義指令的幾種方法 · 學習筆記

[TOC] ## 說明在使用linux時，我們有很多時候可以把自己經常用到的一些腳本做成自己的指令，這樣使得我們在用戶全局都可以使用自定義的指令，那么實現自定指令的方法有哪些呢，今天在這里根據自己的經驗稍微總結一下。 ## 方法一:環境變量法熟悉linux的都知道，大部分發行版都會判斷用戶目錄下是否有`bin`目錄，如果有就會將這個目錄加入環境變量，也就是說，我們可以將一些腳本寫好放到這個目錄下，也就是`$HOME/bin`目錄下，這樣我們就可以在終端直接調用腳本了，上述判斷bin目錄是否存在的部分一般會放在`$HOME/.profile`,我的系統下這部分內容如下： ```bash # ~/.profile: executed by the command interpreter for login shells. # This file is not read by bash(1), if ~/.bash_profile or ~/.bash_login # exists. # see /usr/share/doc/bash/examples/startup-files for examples. # the files are located in the bash-doc package. # the default umask is set in /etc/profile; for setting the umask # for ssh logins, install and configure the libpam-umask package. #umask 022 # if running bash if [ -n "$BASH_VERSION" ]; then # include .bashrc if it exists if [ -f "$HOME/.bashrc" ]; then . "$HOME/.bashrc" fi fi # set PATH so it includes user's private bin if it exists if [ -d "$HOME/bin" ]; then PATH="$HOME/bin:$PATH" fi ``` 當然，如果之前目錄中沒有bin目錄，我們自己手動在`$HOME`目錄下建立`bin`,這個時候需要我們注銷后再登錄才可以，或者執行`source $HOME/.profile`。 ## 方法二:alias方法 bash下我們可以使用`alias`來為一些簡單的命令定義別名，一般這個命令都放在`$HOME/.bashrc`文件下，如下所示： ```bash # ~/.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 "$TERM" in xterm-color|*-256color) color_prompt=yes;; esac # uncomment for a colored prompt, if the terminal has the capability; turned # off by default to not distract the user: the focus in a terminal window # should be on the output of commands, not on the prompt #force_color_prompt=yes if [ -n "$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 "$(dircolors -b)" alias ls='ls --color=auto' #alias dir='dir --color=auto' #alias vdir='vdir --color=auto' #alias grep='grep --color=auto' #alias fgrep='fgrep --color=auto' #alias egrep='egrep --color=auto' fi # colored GCC warnings and errors #export GCC_COLORS='error=01;31:warning=01;35:note=01;36:caret=01;32:locus=01:quote=01' # some more ls aliases #alias ll='ls -l' #alias la='ls -A' #alias l='ls -CF' #mywine alias mwine='WINEPREFIX=/home/yhp/.mywine/deepin_mywine deepin-wine' #個人華為云服務器 alias mhw_server='ssh yhp@139.159.243.162' #掛載個人華為云服務器的 /home/yhp 文件夾到本地 /home/yhp/hw_work_space alias mhw_mount='sshfs yhp@139.159.243.162:/home/yhp /home/yhp/hw_work_space' alias mhw_umount='fusermount -u /home/yhp/hw_workspace' #添加更人密碼到個人密碼管理庫 alias mpasswd='sudo bash ~/.hp_passwd/hp_passwd.sh' # Alias definitions. # You may want to put all your additions into a separate file like # ~/.bash_aliases, instead of adding them here directly. # See /usr/share/doc/bash-doc/examples in the bash-doc package. if [ -f ~/.bash_aliases ]; then . ~/.bash_aliases fi # enable programmable completion features (you don't need to enable # this, if it's already enabled in /etc/bash.bashrc and /etc/profile # sources /etc/bash.bashrc). if ! shopt -oq posix; then if [ -f /usr/share/bash-completion/bash_completion ]; then . /usr/share/bash-completion/bash_completion elif [ -f /etc/bash_completion ]; then . /etc/bash_completion fi fi # Set LS_COLORS environment by Deepin if [[ ("$TERM" = *256color || "$TERM" = screen* || "$TERM" = xterm* ) && -f /etc/lscolor-256color ]]; then eval $(dircolors -b /etc/lscolor-256color) else eval $(dircolors) fi ``` ## 方法三:建立fish shell一樣的函數機制上面兩種方式不太好管理，而fish shell中自定義指令是使用函數的方式來實現的，一條自定義指令可以對應一個函數，于是我們可以借助fish shell的這種思路來在bash上實現。實現方法如下： **建立放置函數的文件夾** 我的方法是在`$HOME`下建立`.bash_func`文件夾，可使用命令 `mkdir -p $HOME/.bash_func`實現。 **在$HOME/.bashrc下添加加載函數的代碼** 在`$HOME/.bashrc`后面添加以下部分， ```bash if [ -d "$HOME/.bash_func" ] then if [[ $(ls $HOME/.bash_func | wc -c ) -gt 0 ]];then for flist in $(ls $HOME/.bash_func) do . $HOME/.bash_func/$flist done fi fi ``` 這樣以來，我們在`~/.bash_func/`下建立文件寫函數，啟動終端后，就能自動加載函數，之后就可以做為自定義的指令使用。 比如，我們建立`t_func`文件，文件內容如下： ``` function t_func(){ echo "hello,this is a demo!" } ``` 然后我們新打開一個終端，注意要新打開，或者你可以先把shell切換到sh，再切換到bash，使得.vimrc文件被加載，然后我們終端輸入`t_func`可以看到效果！ 需要注意的是，要寫成函數的形式，雖然一個文件中可以寫多個函數，但是建立一個文件寫一個函數，一個函數就是一條自定義指令，這樣方便管理！ ## 總結比較 | 方法 | 優點 | 缺點| |:----------:|:--------------:|:-------------:| |環境變量法|管理方便，實現簡單|fork了子模塊，注定有些你想要實現的實現起來可能比較復雜| |alias法|簡單，明了 |如果要實現復雜的，將要寫腳本，在賦別名，不好管理| |函數法|管理方便，實現簡單，函數在終端啟動時就加載完畢|過多的函數可能造成啟動終端較慢，單應該沒有明顯的遲鈍|