bash completion of makefile target

Add this in your ~/.bash_profile file or ~/.bashrc file

complete -W "\`grep -oE '^[a-zA-Z0-9_.-]+:([^=]|$)' ?akefile | sed 's/[^a-zA-Z0-9_.-]*$//'\`" make

This searches for a target in your Makefile titled ‘Makefile’ or ‘makefile’ (note the capital ? wildcard in ?akefile) using grep, and pipes it over to the complete command in bash which is used to specify how arguments are autocompleted. The -W flag denotes that the input to the complete command will be a wordlist which is accomplished by passing the results of grep through sed which arranges it into the desirable wordlist format.

Caveats and gotchas:

1. Your make file is named ‘GNUMakefile’ or anything else other than ‘Makefile’ or ‘makefile’. If you frequently encounter such titles consider changing the regular expression ?akefile accordingly.

2. Forgetting to source your ~/.bash_profile or ~/.bashrc file after making the changes. I add this seemingly trivial detail since, to the uninitiated it is unfamiliar.
   For any change to your bash files to take effect, source them using the command

   source ~/.bashrc
   

   or

   source ~/.bash_profile
   

PS. You also now have the added ability to display the possible make targets by pressing [Tab] twice just like in bash completion. Just make sure you add a space after the command make before typing [Tab] twice.