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using_aliases_in_raspbian

Using Aliases in Raspbian



Aliases are a way of assinging a complex command to an easy to remember word. Looking at the command below:

      ip addr |grep '[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}'


This returns just the IP part of the output from an ip addr command, making the output much easier to read, however remembering and typing the command requires more effort than it saves. For this then we can create an alias.

I want an alias called showip that acutally does the same as typing ip addr |grep '[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}'

You need to edit the .bash file for the logged in user who will use this alias. I am logged in as pi, so I will edit that bash file.\
Navigate to pi home folder:

   cd /home/pi


Show the list of files:

   ls -al to show file list, you will see a list of files, including one called .bashrc\\ 


Edit the .bashrc file by entering:

    sudo nano /home/pi/.bashrc


My default .bashrc file looks like this:

  # ~/.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
  
  # 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'
  
  # 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



Now add the new alias:

      alias showip=" ip addr |grep '[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}'"


save the file and exit:

      ctrl-x - yes - enter


You have to restart the bash for any new aliases to work

      . .bashrc


If you want to see if the alias is now listed, from the command prompt just type:

      alias


You should now be able to type your new command at the command line and get an output:

      showip
          inet 127.0.0.1/8 scope host lo
          inet 192.168.27.30/24 brd 192.168.27.255 scope global eth0



using_aliases_in_raspbian.txt · Last modified: 2017/02/28 18:00 (external edit)