TL;DR
# In ~/.bashrc or your startup file
# Create a directory for history files if needed.
HISTDIR="${HOME}/.history.d"
mkdir -p ${HISTDIR}
# Create a separate history file for each tty.
export HISTFILE="${HISTDIR}/tty`tty|cut -c10-`.hist"
# Append to history rather than overwrite it
shopt -s histappend
If you like to keep multiple terminals open for different purposes and you wanted a way to keep the command history for each of them, and keep them separate, then read on!
I keep separate terminals open for differnet purposes. One terminal is for system maintenance (installing packages, configurations etc). A few terminals for writing, a few for coding, a few for experiments.
The default behavior of bash is to write out the history at the end of each
session, overwriting the default history file (~/.bash_history). This is
unsatisfactory because the history in all the other terminals is important.
I love linux because systems can have uptimes in years, but I usually I have to reboot my laptop once a week to apply security updates that come along. My browser can restart its tabs, but I have to manually reopen all my terminals, and now I’ve lost their history.
Fortunately, we have a solution to the history issue by using the following features bash and the linux kernel offers us:
tty) that tells us which terminal we are currently
on, and each terminal we open gets a unique number.Using these two features we can set things up so that whenever we open a terminal we tell bash to save history to a file tied to the terminal, rather than a common shared file.
Here is the relevant part of my ~/.bashrc
# Create a directory for history files if needed.
HISTDIR="${HOME}/.history.d"
mkdir -p ${HISTDIR}
# Create a separate history file for each tty.
export HISTFILE="${HISTDIR}/tty`tty|cut -c10-`.hist"
# Append to history rather than overwrite it
shopt -s histappend
# These are personal preferences,
# not needed for multiple history files
export HISTCONTROL=ignoredups:erasedups
export HISTSIZE=1000
export HISTFILESIZE=1000
# A creature comfort to remind ourselves that
# we're saving to non default history files
echo "History file: ${HISTFILE}"
With this setup, whenever we open a terminal it either creates or reuses a
history file based on its tty identity allowing us multiple histories for
different terminals that perist across us closing and opening terminals.