I use this on my unix/linux boxes for eternal bash history for all users (place in /etc/bashrc)

if [ "$BASH" ]; then
        export HISTTIMEFORMAT="%Y-%m-%d_%H:%M:%S "
        export PROMPT_COMMAND="${PROMPT_COMMAND:+$PROMPT_COMMAND ; }"'echo "`date +'%y.%m.%d-%H:%M:%S:'`" $USER "("$ORIGINAL_USER")" "COMMAND: " "$(history 1 | cut -c8-)" >> /var/log/bash_eternal_history'
        alias ehistory='cat /var/log/bash_eternal_history'
        readonly PROMPT_COMMAND
        readonly HISTSIZE
        readonly HISTFILE
        readonly HOME
        readonly HISTIGNORE
        readonly HISTCONTROL
fi

Then as root run the commands:

touch /var/log/bash_eternal_history
chmod 777 /var/log/bash_eternal_history
chattr +a /var/log/bash_eternal_history

on BSD freebsd the last command won’t work, use this instead:

# find /var/log -type f -name 'bash_eternal_history' -exec chflags uappnd {} \;

Linux Eternal Bash History One-Liner

Here is a one liner setup for eternal bash history (run as root):

sudo cat <<'EOF' > /etc/profile.d/eternal_bash_history.sh
# eternal_bash_history.sh

# Not running bash?
[ -n "$BASH_VERSION" ] || return 0

# Not an interactive shell?
[[ $- == *i* ]] || return 0


if [ "$BASH" ]; then
        export HISTTIMEFORMAT="%Y-%m-%d_%H:%M:%S "
        export PROMPT_COMMAND="${PROMPT_COMMAND:+$PROMPT_COMMAND ; }"'echo "`date +'%y.%m.%d-%H:%M%S:'`" $USER "("$ORIGINAL_USER")" "COMMAND: " "$(history 1 | cut -c8-)" >> /var/log/bash_eternal_history'
        alias ehistory='cat /var/log/bash_eternal_history'
        readonly PROMPT_COMMAND
        readonly HISTSIZE
        readonly HISTFILE
        readonly HOME
        readonly HISTIGNORE
        readonly HISTCONTROL
fi

# Set up eternal log file and allow all users to write to it
# Do not allow anyone (even root) to modify eternal log or this script
if [ "$EUID" -eq 0 ]; then
 touch /var/log/bash_eternal_history 2>/dev/null
 chmod 777 /var/log/bash_eternal_history 2>/dev/null
 chattr +a /var/log/bash_eternal_history 2>/dev/null
 chattr +a /etc/profile.d/eternal_bash_history.sh 2>/dev/null
fi
EOF