automagical shell alias completion;

• works with all common aliases, even self-aliases;

• one completion function, for all aliases;

• alias completion as easy as type-and-tab;

1. install dependency bash-completion;

   • linux:

     install bash-completion using system package manager:

     dnf install bash-completion     ##  fedora
     apt install bash-completion     ##  debian
     

     for other linux distros, see faq;

   • macos (experimental):

     install bash-completion homebrew formulae version 2:

     brew install bash-completion@2
     

   • windows (experimental):

     see faq;

2. source complete_alias in ~/.bash_completion:

   . {complete_alias}
   

   where {complete_alias} is the path of complete_alias;

1. edit aliases to complete in complete_alias:

   for example, to complete aliases foo, bar and baz:

   complete -F _complete_alias foo
   complete -F _complete_alias bar
   complete -F _complete_alias baz
   

2. to complete an alias, type it and press <tab>;

to complete alias sctl aliased to systemctl:

$ alias sctl='systemctl'
$ cp complete_alias ~/.complete_alias
$ echo ". ~/.complete_alias" >> ~/.bash_completion
$ echo "complete -F _complete_alias sctl" >> ~/.complete_alias
$ sctl <tab>
add-requires
add-wants
cancel
cat
condreload
...

to config complete-alias, set these envars before sourcing the main script:

• COMPAL_AUTO_UNMASK

  this is a bool; default is 0; when set to 1, enables auto unmask; when set to 0, uses manual unmask;

  auto unmask automatically manages non-alias command completions, but incurs a small overhead on source; manual unmask is the traditional way of setting non-alias command completions, which is static and faster but requires user intervention if the preset is not satisfying;

• support for gnu bash(>=4.4) on linux is aimed;

• support for older versions of bash is uncertain;

• support for other shells is possible but unlikely;

• support for other operating systems is experimental;

• how to install it on windows?

  support for windows is limited to msys2 and git for windows:

  • msys2:

    msys2 features pacman so you can install like linux:

    pacman -S bash-completion
    cat complete_alias >> ~/.bash_completion
    

  • git for windows:

    tldr: steal bash_completion and source it before complete_alias;

    git for windows provides git bash, which is a minimal environment based on msys2; for what matters here, git bash does not have package manager; so the above install procedure does not apply;

    the idea is, you must somehow get bash-completion and load it before complete-alias in a shell environment; for example, you can download bash-completion package from a msys2 mirror; however, the easiest solution i found to make things work is to simply download the main script bash_completion from its git repo; this does not give you its entirety, but is good enough to work;

    now you have 2 files: bash_completion and complete_alias; you need to source them in this order in ~/.bashrc:

    . ~/.bash_completion.sh
    . ~/.complete_alias.sh
    

    attention: here we renamed the files; we cannot use ~/.bash_completion because this is the very filename sourced by the very script; using this filename will cause an infinite loop;

    now install is complete; add your own aliases in ~/.complete_alias.sh;

• how to install bash-completion on other linux distros?

  these commands are sourced from wikis and users:

  pacman -S bash-completion               ##  arch
  yum install bash-completion             ##  centos
  emerge --ask app-shells/bash-completion ##  gentoo
  zypper install bash-completion          ##  suse
  apt install bash-completion             ##  ubuntu
  

  these commands are not tested; open a ticket if you find them not working;

• how to complete all my aliases?

  run this one-liner after all aliases have been defined:

  complete -F _complete_alias "${!BASH_ALIASES[@]}"
  

  it works like this:

  complete -F _complete_alias foo
  complete -F _complete_alias bar
  complete -F _complete_alias baz
  ...
  

  note that if you simply put this one-liner in complete_alias code, things may not work, depending on the order of file sourcing, which in turn varies across user configurations; the correct way to use this one-liner is to put it in the same file where aliases are defined; for example, if your aliases are defined in ~/.bashrc, then that file should look like this:

  alias foo='...'
  alias bar='...'
  alias baz='...'
  ...
  complete -F _complete_alias "${!BASH_ALIASES[@]}"
  

• sudo completion is not working correctly?

  there is a known case with sudo that can go wrong; for example:

  $ unalias sudo
  $ complete -r sudo
  $ alias ls='ping'
  $ complete -F _complete_alias ls
  $ sudo ls <tab>
  {ip}
  {ip}
  {ip}
  ...
  

  here we are expecting a list of files, but the completion reply is a list of ip addrs; the reason is, the completion function for sudo is almost always _sudo, which is provided by bash-completion; this function strips sudo then meta-completes the remaining command line; in our case, this is ls to be completed by _complete_alias; but there is no way for _complete_alias to see the original command line, and so it cannot tell ls from sudo ls; as a result, ls and sudo ls are always completed the same even when they should not; unfortunately, there is nothing _complete_alias can do here;

  the easiest solution is to make sudo a self-alias:

  $ alias sudo='sudo'
  $ complete -F _complete_alias sudo
  $ alias ls='ping'
  $ complete -F _complete_alias ls
  $ sudo ls <tab>
  {file}
  {file}
  {file}
  ...
  

  this gives _complete_alias a chance to see the original command line, then decide what is the right thing to do; you may add a trailing space to sudo alias body if you like it that way, and things still work correctly (listing ip addrs is correct in this case):

  $ alias sudo='sudo '
  $ complete -F _complete_alias sudo
  $ alias ls='ping'
  $ complete -F _complete_alias ls
  $ sudo ls <tab>
  {ip}
  {ip}
  {ip}
  ...
  

The source code is licensed under the GNU General Public License v3.0.

Copyright (C) 2016-2021 Cyker Way

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.