Default /etc/bash.bashrc for Ubuntu 20.04

bash.bashrc

# System-wide .bashrc file for interactive bash(1) shells.

# To enable the settings / commands in this file for login shells as well,
# this file has to be sourced in /etc/profile.

# If not running interactively, don't do anything
[ -z "$PS1" ] && return

# check the window size after each command and, if necessary,
# update the values of LINES and COLUMNS.
shopt -s checkwinsize

# 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, overwrite the one in /etc/profile)
# but only if not SUDOing and have SUDO_PS1 set; then assume smart user.
if ! [ -n "${SUDO_USER}" -a -n "${SUDO_PS1}" ]; then
  PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '
fi

# Commented out, don't overwrite xterm -T "title" -n "icontitle" by default.
# If this is an xterm set the title to user@host:dir
#case "$TERM" in
#xterm*|rxvt*)
#    PROMPT_COMMAND='echo -ne "\033]0;${USER}@${HOSTNAME}: ${PWD}\007"'
#    ;;
#*)
#    ;;
#esac

# enable bash completion in interactive shells
#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

# sudo hint
if [ ! -e "$HOME/.sudo_as_admin_successful" ] && [ ! -e "$HOME/.hushlogin" ] ; then
  case " $(groups) " in *\ admin\ *|*\ sudo\ *)
    if [ -x /usr/bin/sudo ]; then
  cat <<-EOF
  To run a command as administrator (user "root"), use "sudo <command>".
  See "man sudo_root" for details.

  EOF
    fi
  esac
fi

# if the command-not-found package is installed, use it
if [ -x /usr/lib/command-not-found -o -x /usr/share/command-not-found/command-not-found ]; then
  function command_not_found_handle {
    # check because c-n-f could've been removed in the meantime
    if [ -x /usr/lib/command-not-found ]; then
      /usr/lib/command-not-found -- "$1"
      return $?
    elif [ -x /usr/share/command-not-found/command-not-found ]; then
      /usr/share/command-not-found/command-not-found -- "$1"
      return $?
    else
      printf "%s: command not found\n" "$1" >&2
      return 127
    fi
  }
fi

If you have altered your /etc/bash.bashrc you can download the original above or use the code below

wget https://gist.githubusercontent.com/Clanwarz/210eca7c3a9153ccecf2a287e3869a62/raw/9a52ccacf2ee4335b020af014ae04335b55ba422/bash.bashrc -O /etc/bash.bashrc
chmod 0644 /etc/bash.bashrc

NOTE: I gain nothing from trying to give you a file that is not legit. If you think otherwise, don't use it. If this can help you, cheers!