Better Bash history | Arabesque

Better Bash history | Arabesque

By default, the Bash shell keeps the history of your most recent session in the .bash_history file, and the commands you've issued in your current session are also available with a history call. These defaults are useful for keeping track of what you've been up to in the shell on any given machine, but with disks much larger and faster than they were when Bash was designed, a little tweaking in your .bashrc file can record history more permanently, consistently, and usefully.

Append history instead of rewriting it

You should start by setting the histappend option, which will mean that when you close a session, your history will be appended to the .bash_history file rather than overwriting what's in there.

shopt -s histappend  

Allow a larger history file

The default maximum number of commands saved into the .bash_history file is a rather meager 500. If you want to keep history further back than a few weeks or so, you may as well bump this up by explicitly setting $HISTSIZE to a much larger number in your .bashrc. We can do the same thing with the $HISTFILESIZE variable.

HISTFILESIZE=1000000  HISTSIZE=1000000  

The man page for Bash says that HISTFILESIZE can be unset to stop truncation entirely, but unfortunately this doesn't work in .bashrc files due to the order in which variables are set; it's therefore more straightforward to simply set it to a very large number.

If you're on a machine with resource constraints, it might be a good idea to occasionally archive old .bash_history files to speed up login and reduce memory footprint.

Don't store specific lines

You can prevent commands that start with a space from going into history by setting $HISTCONTROL to ignorespace. You can also ignore duplicate commands, for example repeated du calls to watch a file grow, by adding ignoredups. There's a shorthand to set both in ignoreboth.

HISTCONTROL=ignoreboth  

You might also want to remove the use of certain commands from your history, whether for privacy or readability reasons. This can be done with the $HISTIGNORE variable. It's common to use this to exclude ls calls, job control builtins like bg and fg, and calls to history itself:

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