how to clear the effect of system wide bashrc

Question

At my company there are system-wide bashrc files like /etc/bashrc and so on.

Inside, they source more and more files. It's very confusing (I noticed my "ls" is aliased with a bunch of flags to ls that I don't want).

I want to for my ~/.bashrc clear the effects of all bashrcs.

Is there something like that in bash? Just to clear all aliases, functions, etc, defined in system-wide files.

Answer 1

The easiest way would be to add this line to your ~/.bashrc :

unalias -a

As far as I know, there is no equivalent for clearing all functions. You can, however, clear them one by one using

unset -f function_name

The following two bash options are also relevant:

  --rcfile file
          Execute  commands  from file instead of the system wide
          initialization file /etc/bash.bashrc and  the  standard
          personal  initialization file ~/.bashrc if the shell is
          interactive (see INVOCATION below).

  --norc Do  not read and execute the system wide initialization
          file /etc/bash.bashrc and the  personal  initialization
          file  ~/.bashrc  if  the  shell  is  interactive.  This
          option is on by default if the shell is invoked as sh.

So, you could set bash to be an alias for bash --norc:

    alias bash='/bin/bash --norc'

That way, every time you manually launch bash a new shell will be started with no initialization files. You would then need to manually source your .bashrc.

I thought you could combine the --norc and --rcfile options to read your ~/.bashrc only but could not get it to work.