Where is this bash shell alias being configured?

Question

While logged in as root onto a CentOS 6.5 system, I run

># alias
alias cp='cp -i'
alias l.='ls -d .* --color=auto'
alias ll='ls -l --color=auto'
alias ls='ls --color=auto'
alias mv='mv -i'
alias rm='rm -i'
alias which='alias | /usr/bin/which --tty-only --read-alias --show-dot --show-tilde'

I want to modify alias ll='ls -l --color=auto' to alias ll='ls -lha --color=auto' for all users. cat /etc/bashrc and cat /root/.bashrc yield, respectively:

># cat /etc/bashrc
# /etc/bashrc

# System wide functions and aliases
# Environment stuff goes in /etc/profile

# It's NOT a good idea to change this file unless you know what you
# are doing. It's much better to create a custom.sh shell script in
# /etc/profile.d/ to make custom changes to your environment, as this
# will prevent the need for merging in future updates.

# are we an interactive shell?
if [ "$PS1" ]; then
  if [ -z "$PROMPT_COMMAND" ]; then
    case $TERM in
    xterm*)
        if [ -e /etc/sysconfig/bash-prompt-xterm ]; then
            PROMPT_COMMAND=/etc/sysconfig/bash-prompt-xterm
        else
            PROMPT_COMMAND='printf "\033]0;%s@%s:%s\007" "${USER}" "${HOSTNAME%%.*}" "${PWD/#$HOME/~}"'
        fi
        ;;
    screen)
        if [ -e /etc/sysconfig/bash-prompt-screen ]; then
            PROMPT_COMMAND=/etc/sysconfig/bash-prompt-screen
        else
            PROMPT_COMMAND='printf "\033]0;%s@%s:%s\033\\" "${USER}" "${HOSTNAME%%.*}" "${PWD/#$HOME/~}"'
        fi
        ;;
    *)
        [ -e /etc/sysconfig/bash-prompt-default ] && PROMPT_COMMAND=/etc/sysconfig/bash-prompt-default
        ;;
      esac
  fi
  # Turn on checkwinsize
  shopt -s checkwinsize
  [ "$PS1" = "\\s-\\v\\\$ " ] && PS1="[\u@\h \W]\\$ "
  # You might want to have e.g. tty in prompt (e.g. more virtual machines)
  # and console windows
  # If you want to do so, just add e.g.
  # if [ "$PS1" ]; then
  #   PS1="[\u@\h:\l \W]\\$ "
  # fi
  # to your custom modification shell script in /etc/profile.d/ directory
fi

if ! shopt -q login_shell ; then # We're not a login shell
    # Need to redefine pathmunge, it get's undefined at the end of /etc/profile
    pathmunge () {
        case ":${PATH}:" in
            *:"$1":*)
                ;;
            *)
                if [ "$2" = "after" ] ; then
                    PATH=$PATH:$1
                else
                    PATH=$1:$PATH
                fi
        esac
    }

    # By default, we want umask to get set. This sets it for non-login shell.
    # Current threshold for system reserved uid/gids is 200
    # You could check uidgid reservation validity in
    # /usr/share/doc/setup-*/uidgid file
    if [ $UID -gt 199 ] && [ "`id -gn`" = "`id -un`" ]; then
       umask 002
    else
       umask 022
    fi

    # Only display echos from profile.d scripts if we are no login shell
    # and interactive - otherwise just process them to set envvars
    for i in /etc/profile.d/*.sh; do
        if [ -r "$i" ]; then
            if [ "$PS1" ]; then
                . "$i"
            else
                . "$i" >/dev/null 2>&1
            fi
        fi
    done

    unset i
    unset pathmunge
fi
# vim:ts=4:sw=4

and

># cat /root/.bashrc
# .bashrc

# User specific aliases and functions

alias rm='rm -i'
alias cp='cp -i'
alias mv='mv -i'

# Source global definitions
if [ -f /etc/bashrc ]; then
        . /etc/bashrc
fi

It's /etc/profile.d/colorls.sh that contains two references to ll:

># cat /etc/profile.d/colorls.sh
# color-ls initialization

#when USER_LS_COLORS defined do not override user LS_COLORS, but use them.
if [ -z "$USER_LS_COLORS" ]; then

  alias ll='ls -l' 2>/dev/null
  alias l.='ls -d .*' 2>/dev/null


  # Skip the rest for noninteractive shells.
  [ -z "$PS1" ] && return

  COLORS=

  for colors in "$HOME/.dir_colors.$TERM" "$HOME/.dircolors.$TERM" \
      "$HOME/.dir_colors" "$HOME/.dircolors"; do
    [ -e "$colors" ] && COLORS="$colors" && break
  done

  [ -z "$COLORS" ] && [ -e "/etc/DIR_COLORS.256color" ] && \
      [ "x`tty -s && tput colors 2>/dev/null`" = "x256" ] && \
      COLORS="/etc/DIR_COLORS.256color"

  if [ -z "$COLORS" ]; then
    for colors in "/etc/DIR_COLORS.$TERM" "/etc/DIR_COLORS" ; do
      [ -e "$colors" ] && COLORS="$colors" && break
    done
  fi

  # Existence of $COLORS already checked above.
  [ -n "$COLORS" ] || return

  eval "`dircolors --sh "$COLORS" 2>/dev/null`"
  [ -z "$LS_COLORS" ] && return
  grep -qi "^COLOR.*none" $COLORS >/dev/null 2>/dev/null && return
fi

alias ll='ls -l --color=auto' 2>/dev/null
alias l.='ls -d .* --color=auto' 2>/dev/null
alias ls='ls --color=auto' 2>/dev/null

So, do I edit /etc/profile.d/colorls.sh, and if yes, in both places where ll shows up? Or is there a better way to go about it?

Answer 1

If all your users have .bashrc with a reference to execute /etc/bashrc, then adding a line at the bottom of that file would be a good place to make this modification overwriting the previous alias.

At the bottom of /etc/bashrc add some comments and the new alias, like:

# Setting ll alias -- August 2014
# by XXXX

alias ll='ls -lha --color=auto'

I think this is a clean and simple alternative to modify colorls.sh.

Edit:

Yes, you are right. A better approach would be to create /etc/profile.d/custom.sh and add the alias there.

In fact, I should fix my answer.

Just create the file /etc/profile.d/custom.sh, add your customizations there and set the execution flag for it.

Additional information that can be useful: http://www.thelinuxdaily.com/2010/08/setup-a-universal-user-profile-with-etcprofile-dcustom-sh/