Sunday 18 October 2009

Howto: Sync Bash History Between Terminals

Do you want to be able to use the history from another terminal quickly and simply in a new terminal, or to be able to use any one of the terminals on your desktops to continue working with a current history?

Me too :]

This is a very easy tweak and makes a lot of sense to most people. So we need to edit the file ~/.bashrc

gedit ~/.bashrc

At the bottom paste in the following:

shopt -s histappend
PROMPT_COMMAND="history -n; history -a"
unset HISTFILESIZE
HISTSIZE=2000


Unsetting HISTFILESIZE just gets rid of the filesize limitation, and we rely on HISTSIZE which allows 2000 lines in the file, both normally default to 500.

PROMPT_COMMAND tells bash to reload history and append to history each time it draws the prompt in the terminal.

The only thing to note is if you jump from one terminal to another and wish to recall the last history line from the former terminal, press enter once with a blank line, this causes bash to draw the prompt and sync, if you only just opened the second terminal then you don't have to. The sync only occurs when the prompt is drawn, nothing else to note.

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